Captain America is a huge baseball fan and loves to collect Baseball cards.
Heavy from Team Fortress 2 loves collecting old coins, when he wants to lessen his collection he melts his coins down to make bullets.
Kakashi from Naruto has a bit of a strong collection, he likes collecting Risqué adult novels that Jiraiya makes, his favorite series is called Make-Out.
According to Dr.Star-line, Dr. Eggman is a gamer who has a separate wifi tower exclusively for gaming, which means Dr Eggman loves playing Mario games out of Spite right?
Squidward loves painting self portraits, he is actually quite the good artist, if only he painted other things other than himself.
Kim Possible collected Cuddle Buddies, which the real world equivalent at the time would be Beanie Babies.
In Ed, Edd n Eddy, Ed collects sponges in his basement bathroom's wall, this collection is also kind of a major secret that he keeps to himself.
Dib from Invader Zim Collects Haunted Gummie Bears:
And lastly According to the "Those Meddling Kids" interviews, Shaggy has the largest collection of decorator Belt Buckles in the world with a total of 653. He wears a different buckle for every mystery.
