Dragnet to Hogan's Heroes

The main characters from Adam-12 appear as witnesses in an episode of Dragnet

Emergency! had a crossover with Adam-12 to find a boy who ran away from the hospital.

Both feature the fictional Trans Global Airlines

Diagnosis Murder's Dr Mark Sloan was defended by Matlock when Sloan was accused of murder

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.

Make Room for Grandaddy's Williams had Here's Lucy's Lucy Carter as a houseguest

Make Room For Daddy was continued as Make Room For Grandaddy

The Danny Thomas Show was originally called Make Room For Daddy (and in syndication all episodes are called

The Bill Dana Show's Jose Jimenez also appeared as a person sticking his head out the window in a different episode of Batman.

Hogan's Heroes Colonel Klink has an explicable but existent cameo in an episode of the 1960s live action Batman