Promised Land to Vinnie & Bobby

Promised Land's Russell Greene helped his boss Ryan Matthews face his families past, then Ryan crossed-over onto Diagnosis Murder to ID the body of one of his ex-wife's old friends

Mannix returned to TV on an episode of Diagnosis Murder to solve an old unsolved case with the help of Dr Mark Sloan.

Here's Lucy's Lucy Carter and Mannix's Mannix are held hostage in an episode of Here's Lucy.

Here's Lucy's Mary Jane Lewis was originally a character on The Lucy Show (also called The Lucille Ball Show).

Mr. Mooney from The Lucy Show was on Hi Honey, I'm Home!

Leave it to Beaver's June Cleaver crossed over onto Hi Honey, I'm Home!

Eddie Haskell from Leave it to Beaver appeared on Parker Lewis Can't Lose

Bud Bundy from Married...with Children showed up on Parker Lewis Can't Lose

Vinnie & Bobby was a spin off of Married...with Children original titled Top of the Heap