Dennis the Menace to Dragnet 67

Dennis The Menace "helped" Donna Stone redecorate her house on The Donna Reed Show

The Donna Reed Show crossed over onto Hi Honey, I'm Home!.

Alice & Trixie from The Honeymooners crossed over onto Hi Honey, I'm Home!

Here's Lucy's Lucy was driven around Miami by Ralph Cramden of The Hooneymooner's

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

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

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

Both feature the fictional Trans Global Airlines

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

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

Dragnet spun off Dragnet 67