1. The Munch-verse
It's John Munch's world, and we're all just living in it.

John Munch came out with a bang on Homicide: Life on the Street. When the show was canceled, the character was moved to Law & Order: SVU where he became a staple. Since then, John Munch hasn't stopped showing up on TV and probably never will till the end of time.

He pops up as an undercover federal agent on Arrested Development and teaches Tobias how to scrapbook, in the hopes of getting Mr. Never-Nude to spill the Bluth family secrets. On both The X-Files and The Wire, Munch serves as an officer for the Baltimore Police. Years later, he makes a cameo on 30 Rock after Jenna Maroney lands a guest role as a corpse on Law & Order: SVU. Of course, John Munch's greatest appearance is as a muppet on the Sesame Street sketch "Law & Order: Special Letters Unit." John Munch sure is in high demand, and we're certainly not complaining.