Columbo to One Life to Live

Lou Grant centered around Lou as editor of the fictional Los Angeles Tribune which has been featured on Columbo

Lou Grant spun off of The Mary Tyler Moore Show

The Mary Tyler Moore Show's Georgette Baxter 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

All My Children and Loving feature the fictional Trans Global Airlines

All My Children and One Life to Live crossed over a number of times