Team Free Will
Team Free Will. One ex-blood junkie, one dropout with six bucks to his name, and Mr. Comatose over there. Awesome.
After Dean sarcastically named himself, Sam, and Castiel as "Team Free Will," it was quickly picked up through fandom as shorthand for referring to their alliance in stopping the Apocalypse. It has also been adopted to include Bobby, who was mentioned by Castiel as being a figure in stopping Heaven's plans.
And of course, I remember the most remarkable event. Remarkable because it never came to pass. It was averted by two boys, an old drunk, and a fallen angel.
The concept of "Team Free Will" has persisted and is used again by Dean in a sarcastic manner as they try to find Lucifer's soon-to-be born Nephilim child.
We. You, me, and Sam, we're just better together. So now that you're back, let's go, Team Free Will. Let's get it done.
A number of fans use it to indicate they do not have either a character or shipping allegiance and support all three characters.
"Team Free Will" is also used sometimes to describe fanfics which feature Dean, Sam, and Castiel in a sexual relationship. See Dean/Sam/Castiel.