Angel Eyes
From Super-wiki
Angel Eyes are the eyes of an Angel.
9.10 Road Trip
Gadreel shows his eyes upon returning to his first vessel.
11.09 O Brother Where Art Thou?
Lucifer shows his eyes during his return.
12.19 The Future
Castiel shows his eyes while being empowered by Lucifer's unborn son.
14.10 Nihilism
Michael menacingly shows his eyes.