Everyone loves a nickname, and Supernatural has plenty for the characters, the actors, and of course the fans ourselves.
When Supernatural started, SN was used as an abbreviation for the show on things such as Livejournal community names, for example the original sn_newsletter. The crew also used the abbreviation "SN," as in the yearly issued . However some fans found it could be confused with the TV show and fandom for "Sports Night", while SNL was associated with Saturday Night Live. So SPN became the commonly used abbreviation. Its usage spread even more widely with the advent of the letter economical Twitter.
SPN (pronounced "ess pee en") is usually capitalised and was originally used to refer to both the show and the fandom. Over time however, as the fans and the crew began to refer to each other as "members of the SPN family," and the term "SPN family" has become used more often in reference to fans with "SPN" reserved for the show itself.
Sam and Dean
While not exactly a nickname, the most common term used to refer collectively to Sam and Dean is "the boys." This term originated on the show, as used by older characters such as Bobby, John Winchester and Ellen Harvelle, but was quickly adopted by fans and crew members to refer either to both Sam and Dean or Jared and Jensen. Likewise, these characters have all referred to them in the singular as "boy." Crowley greets Sam and Dean on several occasions by saying "Hello, boys". Abaddon and Irv Franklin also refer to them as "boys" on a few occasions in 9.02 Devil May Care, as do background characters throughout the show.
As for themselves, Sam and Dean have a childish habit where Dean calls Sam "Bitch" and Sam responds with "Jerk". While this exchange became strongly associated with the characters in the fandom, it has only been used six times in the the show. (See  for the full list.)
Most commonly, it's the Winchester's adversaries who refer to them by a variety of pejorative epithets:
- Uriel refers to Dean, and all humans, as "mud monkeys"
- Atropos, Crowley and finally Castiel himself, refer to Sam and Dean as Cas' "pets".
- Interestingly, Sam is called Chachi by Gordon and then Dean by Pamela. This is a reference to Chachi from "Happy Days" and "Joanie Loves Chachi".
- Abaddon calls the boys "Howdy and Doody".
Probably the most expressive term is used by the ever articulate Crowley who calls them "denim-wrapped nightmares".. He also calls them the Hardy Boys, a term long-used in the Television Without Pity recaps of Supernatural. That forum also referred to the boys in 2005/06 as The Brothers Dean. This related to Jared's previous role as Dean Forrester on Gilmore Girls. Occasionally Sam was referred to as Cute!Dean and Dean as Hot!Dean.
Crowley also calls Sam and Dean "Moose and Squirrel," respectively, referring to the cartoon duo of Bullwinkle (the moose) and Rocky (a squirrel) and Timon and Pumbaa who are a cartoon meerkat and warthog duo who first appeared in Disney's 1994 animated film The Lion King. Crowley's caller id for Dean is Not Moose. 
Frank Devereaux compares the two to Cheech and Ed from Ma Bell while they are costumed as electricians while undertaking surveillance.
If you say their names fast enough together, Sam and Dean becomes "Salmon Dean," spawning the title of a track on the show's OST as well as a barrage of interesting fan works after a J2 panel at JiBcon 2016 (recorded by a fan here).
Dean: House rules, Sammy. Driver picks the music, shotgun shuts his cakehole.
Sam: You know, Sammy is a chubby 12 year old. It's Sam, okay?
– Sam and Dean, 1.01 Pilot
Dean's nickname for Sam is "Sammy," generally used either for teasing or in moments of great emotion. While Sam initially protests its use after he and Dean first reunite in 2005, it becomes clear it has as much meaning for Sam as it does for Dean when Gordon Walker uses it and Sam retorts "He's the only one who gets to call me that.". For a count of every time Dean uses this nickname see Sammy.
Many fanworks involving Wincest have Dean call Sam "baby boy." This term has never been used in canon, as Dean generally refers to Sam as "Sammy" or, less often, "little brother."
Other characters throughout the show also reference Sam as Dean's little brother, including Benny, Lucifer and Michael. Going one step further, Michael refers to Sam as Dean's "darling little Sammy".. (Darling Sammy was also the nickname for Sam in the Television Without Pity recaps by Demian. ) Cole Trenton also calls Sam "Sammy" at their second encounter.
In 3.01 The Magnificent Seven, a demon gives Sam the nickname "The Boy King" in reference to Azazel's plan to have Sam lead Hell's army. Fans adopted the nickname and frequently use it for AU fanworks in which Sam is evil, often playing the role Azazel intended. Along the same vein, when Castiel first meets Sam, he refers to him as "The boy with the demon blood."
Many of the nicknames Sam receives both in canon and fandom refer to Sam's Height, such as:
Crowley in particular has a number of nicknames based on Sam's height including "Moose" and "Jolly green." In fact,"Moose" has became so popular with Crowley that it spread to Jared, other cast members, and the fans. (See all its uses in canon here.)
In 7.09 How to Win Friends and Influence Monsters, the waiter Brandon refers to Sam as Big Bird.
In 8.02 What's Up, Tiger Mommy? Crowley calls Sam "Samantha," possibly a reference to his longer hair in Season 8. However, he continues to use "Samantha" intermixed with his other nicknames through Season 11.
There are also nicknames for the various incarnations of Sam:
- Evil!Sam - the name given by fans to Sam when he was possessed by the Meg!Demon. Over time the term has come to have a broader use, especially in fanfiction where there is a whole genre based on the premise of Sam becoming evil.
- Samifer - used by fandom to describe when Sam is Lucifer's vessel.
- Sampala - used by fandom to describe when Sam is transformed into the Impala by Gabriel.
- RoboSam - used by Dean to describe Sam when he didn't have a soul. and was widely used by fans and TV reviewers. Other terms used included Soulless!Sam or Not!Sam. Sam with a soul was occasionally referred to as soulful Sam and Care Bear Sam Source.
- Leviathan!Sam - for when a leviathan poses as Sam.
- Sazekiel or "Sadreel" -used by fandom to describe when Sam is Gadreel's vessel.
Jared seems to prefer the nickname "Sam Fucking Winchester."
Sam doesn't really have a nickname for Dean. He just calls him "Dean." A lot. A popular fandom nickname, particularly in Wincest fanfic, is "Dee." It's hotly debated amongst fans whether Sam has actually used the term in the series. The consensus seems to agree that he hasn't, although there are some instances as recently as season 11 where it's really hard to say.
Gabriel and Cole are both known for calling him "Dean-o".
Whereas Sam is usually referenced by his height, nicknames for Dean often reference his good looks. For instance, Ghostfacer Ed Zeddmore calls him "chisel chest", and Brandon, a waiter at Biggerson's Restaurant, refers to him as "Ken Doll" as he serves him a turducken slammer.
- Alastair: Now we're getting somewhere. Holy water? Come on. Grasshopper, you're gonna have to get creative to impress me.
Alastair also quotes a prophecy supposedly about Dean, calling him a "righteous man,":
- Alastair:And it is written that the first seal shall be broken when a righteous man sheds blood in hell. As he breaks, so shall it break.
Castiel repeats the nickname again later in the same episode:
- Castiel: The righteous man who begins it is the only one who can finish it. You have to stop it.
In 7.11 Adventures in Babysitting, Frank Devereaux also calls Dean Grasshopper, alongside a variety of seemingly random nicknames including Sweetie pops, Buster Brown, My Little Lamb, Tarzan, and Cupcake.
Crowley occasionally calls Dean "Squirrel" and "not Moose" as a play off his nickname for Sam.
There are also nicknames for the various incarnations of Dean:
- Not!Dean - fan nickname for the shapeshifter who takes on Dean's appearance in 1.06 Skin.
- Future!Dean - used for the Dean of 2014 in the popular AU episode 5.04 The End.
- Leviathan!Dean - for when a leviathan poses as Dean.
- Demon!Dean - used by fandom to describe when Dean is turned into a Knight of Hell by the Mark of Cain at the start of season 10. The CW tried to get "Deanmon" up as a nickname. Like "fetch", they couldn't make it happen. (Although the popular parody by the The Hillywood Show including the term may have helped its use.)
Dean: Woah!! Listen to her purr! Have you ever heard anything so sweet?
Sam: You know, if you two want to get a room, just let me know, Dean.Dean: Don't listen to him, baby. He doesn't understand us.
Dean's term of endearment for his beloved Impala, first used in 2.03 Bloodlust, is "Baby". This is commonly used in fandom and by the cast and crew. Dean uses the diminutive in the following episodes: 2.03 Bloodlust, 2.05 Simon Said, 3.08 A Very Supernatural Christmas, 6.15 The French Mistake, 7.06 Slash Fiction, 7.01 Meet the New Boss, 8.02 What's Up, Tiger Mommy? and 9.04 Slumber Party.
The nickname Metallicar originated on Television Without Pity on October 11, 2005 source. It was coined because Dean enjoys listening to classic rock music like Black Sabbath, Led Zeppelin and, of course, Metallica while driving. It became commonplace throughout fandom, and has appeared on merchandise. It diminished in usage over later seasons, replaced by "Baby".
Cas is a nickname for Castiel, first used by Dean in  and later commonly by other characters. Before its use in canon there were relatively few instances of this diminutive in fandom, and when it did appear it was generally pilloried. Subsequently its use became widespread. The show's writers spell the nickname "Cass" (example), and it also appears that way in Tie-in novels. It is spelled Cass in the Season 7 promo. In fandom, and particularly in Fanfiction, it is almost exclusively spelled "Cas". One theory as to the spelling "Cass" is that the writers based Castiel on the angel Cassiel, best known in popular culture from the movies Wings of Desire and the American remake City Of Angels.
Including being the first to call Castiel "Cas," Dean gives him a number of nicknames, including "junkless," "Happy Meal," "little nerdy dude with wings" and (when he's without powers) "baby in a trench coat."
Meg refers to Castiel as "unicorn," "tree-topper," and predominantly as "Clarence" in a reference to the angel in the movie It's a Wonderful Life. In 9.03 I'm No Angel, Castiel adopts the name Clarence as a cover when he is human.
Crowley calls Castiel a giraffe, among other endearments.
Metatron refers to him as Asstiel on several occasions.
Amara calls him blue eyes.
He has also been called Feathers by multiple people at multiple times.
There are also nicknames for the various incarnations of Castiel:
- Clairestiel - the mashup nickname for Castiel while he is possessing Claire Novak as a vessel.
- Thingstiel - Castiel in his true form (briefly described but never seen in the show)
- Future!Castiel - the AU version of a human drug and sex-addicted Castiel from the AU episode 5.04 The End.
- Godstiel - after he has absorbed the souls of Purgatory and proclaimed himself a god.
- Leviathan!Castiel - while he is taken over by the Leviathans inside of him.
- Casifer or Lustiel - Castiel while he is possessed by Lucifer.
In response to Crowley referring to him as "Squirrel" Dean on one occasion calls Crowley "Boris" and refers to Rowena as "Natasha", In the animated series The Rocky and Bullwinkle Show starred a moose called Bullwinkle and a squirrel called Rocky - the source of Crowley's nicknames for the Winchester's. Their nemesis were secret agents of the nation of Pottsylvania: the rather diminutive Boris Badenov and Natasha Fatale.
When Genevieve Padalecki (then Cortese) was cast as Ruby in Season 4, her version of the character became known as Ruby 2.0, New Ruby or its contraction Nuby. Katie Cassidy's Ruby became known as Old Ruby.
The demon Casey reveals that Azazel is the true name of the demon the Winchesters have been hunting in Season Three. In Season 1, he is referred to as "the thing that killed Mom and Jess" and subsequently, after John reveals he knows what it is, as The Demon. In Season 2, Dean refers to him as The Yellow-Eyed Demon. Fannish shorthand for this was YED.
- John Winchester : By fans as Papa Winchester and on TWOP - as the Lying Liar That Lies. Reviewers at TV Guide have been calling John Winchester "Big Daddy Winchester" since Season 1 Source.
- Lucifer: Gabriel called him "Luci" in 5.19 Hammer of the Gods and he is often referred to as such by fans too. He is called Samifer when possessing Sam. Hallucifer is a fan-created nickname for Sam's hallucinations of Lucifer which originated in the LJ community ontd_spnparty's 7x01 Party Post. source
- Gabester - mashup nickname coined after the Trickster was revealed as the archangel Gabriel.
- Sampa: Term coined by fandom in early Season 6 for Samuel Campbell to distinguish him from Sam.
- Victor Henriksen - who needed a nickname because no-one could spell his real name - dubbed "Agent Scooter Javert Bad Assitude" on Television Without Pity
- Abaddon - dubbed by Crowley as "the world's angriest ginger".
Cast and Crew Nicknames
Well obviously we both call each other J, and when anybody says "Alright J, they're ready for you", they generally get both of us. (Points to Jared) J-Rod. I call him J-Rod. The crew, he gets J-Rod. And then I get Jackles. Yeah J-Rod and Jackles are probably the two most commonly used.
The most popular fannish terms are J2 or J-squared. The term "J-squared" was used by Misha in the episode 6.15 The French Mistake. Jared and Jensen are also referred to as "the boys" by both fans and fellow cast and crew. The portmanteau "Padackles" was popular in the first couple of seasons of the show.
In a January 2007 issue of Pop Star magazine, it reported that Smeckles was Jared's nickname for Jensen. At EyeCon April 2008 Jared listed some nicknames for Jensen, including Smackles and Ugly, and mentioned Stretch for himself. (Video)
In fandom, Jared often attracts many of the same nicknames as Sam, which is not surprising given they are the same height. Moose became popular after its use in the show and at conventions, and especially following Jared joining Twitter. Puppy is another commonly fannish nickname, referring to Jared's boundless energy, affectionate nature and good humour.Also J-Pad.
Adding the prefix "Pada" to anything is a common fannish habit: Padacock is a fannish nickname for Jared's penis, while his and Genevieve's first child Thomas was referred to as the Padabump and as mini-Moose after he was born. The on-set logistics around the impending birth were known as "Operation Moose Drop"
- J2 be used in combination with other actors eg J2M refers to Jared, Jensen and Misha, J2M2 refers to Jared, Jensen, Misha and Mark Sheppard.
- "Sir" is the nickname for Jeffrey Dean Morgan in the ONTD community - ontd_spnparty as well as CAPSLOCK SPN. Sir is always on topic.
- Misha on Twitter is known as the Overlord. Other nicknames also include Mish Mish.
- Richard Speight Jr.: Pepsi Angel was nickname used to refer to Richard Speight Jr.that arose (probably first at Facebook) from Richard's Pepsi Max commercials, and after his appearance at Salute to Supernatural Chicago 2010, where he was completely dressed in Pepsi Max clothes.
- Mark Pellegrino: Marksha - an nickname of complex origins from Mishaland a CAPSLOCK COMMUNITY.
- Chad Michael Murray: Mayhem - a nickname arising from RPS fanfic.
- Eric Kripke was generally referred to by fans as Kripke, or occasionally The Kripkeeper or Kripmeister.
- Disappointingly, fans have failed to refer to Jeremy Carver as "The Carver"
- According to the Supernatural: Official Magazine Issue #18 writing team Andrew Dabb and Daniel Loflin were dubbed "Dandrew" when they joined the writer's room.
- Location manager Russ Hamilton is known as "Movie God"
- 1st Assistant Director Kevin Parks is known as Parksapedia because of his encyclopedia knowledge of everything Supernatural.
- 1st Assistant Director Johnny MacCarthy is known as Johnny Mac.
Then most commonly used term for the fandom is SPNFamily.
When the Supernatural fandom began, fans would occasionally discuss collective terms that could be applied to Supernatural fans, similar to "Trekkies or Trekkers" for Star Trek fans, or "Whovians" for fans of the Doctor Who. Discussions were had, polls conducted, suggestions such as rocksalters, saltgunners, renegades and roadies canvassed, but nothing ever stuck.
Super fans has been used occasionally - possibly coined by TV Guide reviewer Matt Roush is response to a fan postcard campaign in February 2007 source. In the show Becky Rosen is referred to more than once as Sam's "super fan" 
Around early 2011, the term "Supernatural Family" came into circulation, used at first by Jared to describe how he felt about the relationship between the cast, crew and fans: "It's like my third family," he says of his fans. "I have my family, my on-set family, and then our 'Supernatural' family, so I love them. My 'Supernatural' family's the biggest and strongest, so I love 'em." . He also used it at the Comic Con 2011  The usage spread amongst other crew members on Twitter such as Jim Michaels.
For the 2013 People's Choice Awards, there was also a new category for "Favorite TV Fan Following". The Supernatural fandom was referred to as "Dean Girls, Sam Girls, and Misha Wives". Within hours of the polls opening, fan complaints about this led to it being changed to SPN Family. We won the award!
Although not widely used, Jensen fans are sometimes called (usually by themselves) Ackleholics, and Jared fans are Padafans or Padaphiles.
Fans of Divine: The Series have been dubbed Divinites.
Of course most fans have individual online 'nicknames' or handles that we use on the social media site, message board or websites we are involved with.
Anyway, I'll think of you as friends not followers. But then again, maybe minions is a better term... I'll percolate.
– @mishacollins 2:07 PM May 13th 2009, Twitter
Misha started the tradition in Supernatural fandom of the Twitter followers of particularly cast or crew being granted a particular name. The following are those currently in use:
- Misha's Minions. In the meta episode 6.15 The French Mistake, Misha calls them MishAmigos.
- Jared's Moosekateers
- Jim Beaver's Twidjits
- Jim Michaels' Jimions
- Russ Hamilton's Russticles
- Mark Sheppard's followers are known as Bob, so dubbed by Mark source.
- Traci Dinwiddie's T~bugs
- Matt Cohen's Coheners
- Colin Ford's Colinites
- Kim Rhodes's Rhodies
- Tara Larsen's Larsenists
- Sebastian Roche's Acolytes
- Richard Speight Jr.'s Twicksters
- Rob Benedict - Chuck's chicks or Rob's Roadies
- Todd Stashwick's DracPac
- Chad Lindberg's Chadlings & Badasses
- Clif Kosterman occasionally used Duckers after the rise of Duck Nation, since 2013 uses Clifhangers
- Gabriel Tigerman - Gabe's babes
- Rick Worthy's Betas
- Mark Pellegrino - Lucifer's legionnaires
- Ivan Hayden's Resistors
- Todd Aronauer's Aronauts
- Divine: The Series Divinites
- DJ Qualls' Garth Vaders
- Alaina Huffman's Ginger Knights
- Travis Aaron Wade's Wadestars
The Supernatural Wiki began life as a website called Super Canon in early 2006. When it transformed into the wiki format in August 2006, the name Supernatural Wiki was our new official name. But the nickname Super Wiki soon stuck and became widely used, especially when we adopted it as our Twitter handle in late 2008.
- 6.07 Family Matters
- 6.07 Family Matters
- 7.23 Survival of the Fittest
- 9.10 Road Trip
- 9.16 Blade Runners
- 1.01 Pilot
- 2.10 Hunted
- 2.20 What Is and What Should Never Be
- 10.01 Black
- 10.05 Fan Fiction
- 10.04 Baby
- 4.07 It's the Great Pumpkin, Sam Winchester
- 6.17 My Heart Will Go On
- 6.20 The Man Who Would Be King
- 7.01 Meet the New Boss
- 2.03 Bloodlust
- 4.15 Death Takes a Holiday
- 9.06 Heaven Can't Wait
- 5.10 Abandon All Hope...
- 8.02 What's Up, Tiger Mommy?
- 8.17 Goodbye Stranger
- 10.11 There's No Place Like Home
- 5.13 The Song Remains the Same
- 10.15 The Things They Carried
- 4.07 It's the Great Pumpkin, Sam Winchester
- 6.21 Let It Bleed
- 2.14 Born Under a Bad Sign
- 5.22 Swan Song
- 5.08 Changing Channels
- 7.06 Slash Fiction
- 9.01 I Think I'm Gonna Like It Here
- Buddy TV set interviews Sept 2008
- 3.13 Ghostfacers
- 4.04 Metamorphosis
- 6.19 Mommy Dearest
- 6.10 Caged Heat
- 7.17 The Born-Again Identity
- 8.17 Goodbye Stranger
- 4.20 The Rapture
- 6.22 The Man Who Knew Too Much
- 11.10 The Devil in the Details
- 6.04 Weekend at Bobby's
- 3.04 Sin City
- 9.10 Road Trip
- 5.01 Sympathy for the Devil
- 7.08 Season Seven, Time for a Wedding!
- Jared interview with Zap2It
- Nerd HQ session