Daredevil Season 2 (2016) - In the comics, Melvin Potter is the alter ego of a semi-villain called The Gladiator. When he shows daredevil the armor he's wearing, The Gladiator's Logo is on it.
In Spongebob Squarepants, when SpongeBob is beatboxing/rapping in the Krusty Krab pizza episode, his hat is on backward.
In The Simpsons "Homer the Vigilante" last scene, there are four trees forming a W referencing the movie that features It's a Mad, Mad, Mad, Mad World.
In S04E02 of Friends, the guy who robbed Chandler and Joey wrote "Thanks for all your stuff!" on the Magna Doodle Board.
In S04E14 of The Office, Michael Scott swallows his toothpaste.