Mannix to The Many Loves of Dobie Gillis

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

Here's Lucy's Mary Jane Lewis was originally a character on The Lucy Show (also called The Lucille Ball Show).

Mr. Mooney from The Lucy Show was on Hi Honey, I'm Home!

Many Loves of Dobie Gillis' title character crossed over onto Hi Honey, I'm Home!