City of Angels to Melrose Place

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

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.

The airplane that crashed and strand the cast of Lost was Oceanic Airlines Flight 815 also featured on Diagnosis Murder.

In an episode of Veronica Mars, Veronica's fortune cookie had the numbers that won Hurley from Lost the lottery.

The mugshot of Malcolm T Wiggins from the X-Files episode "Titonus" appears on the wall of a police interrogation room in the Veronica Mars episode "Leave it to Beaver." Also the fictional car rental company Lariat where Mulder & Scully always rented their cars was featured prominently on the Veronica Mars episode "Rat Saw God."

Brenda Walsh picks up a Morley smoking habit while in Paris on Beverly Hills 90210

Kelly Taylor from Beverly Hills 90210 and Jake Hanson from Melrose Place dated to launch Melrose Place's spinoff