Dennis the Menace to The Bob Cummings Show

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 was visited in two episodes by The Bob Cummings Show's Bob Collins.