Several others appeared in walk-ons. The Cartwrights, from Bonanza, Paladin, and several others appear.
There was the hurricane that swept through Golden Girls, Empty Nest and some other show I can’t remember that was in the same universe.
I didn’t watch the shows before or after Murphy Brown, but I remember two story threads that went through the CBS Monday lineup. One was about a low-speed chase a la OJ, the other was about Liz Taylor’s diamonds being stolen.
SmartAleq, Mork started out on Happy Days because Garry Marshall, while very high on Robin Williams himself, wanted to see how audiences reacted before giving him his own show. Mork and Mindy premiered shortly afterwards, and Mork did make another guest appearance after that. Also, Mork once made a totally gratuitous guest appearance on the premiere of another ABC (non-Marshall) show.
And I don’t know if this counts as a crossover, but I clearly remember Daffy Duck applying for a job with Drew Carey.
Don’t forget the greatest series of cross-overs ever, between the Beverly Hillbillies, Green Acres, and Pettycoat Junction. Hooterville must have been a hoot!
Dang, just beat me. Both BH and GA interacted with PJ, but I can’t recall BH and GA interacting with each other.
3rd Rock From The Sun had Dick & Mary (played by Jane Curtin) visit a Science Fiction convention. There was a priceless look on Mary’s face when they passed a couple of people dressed as Coneheads. (For all you young 'uns, Jane Curtin was an original Conehead on SNL).
Really? Eb and Ellie were sweet on each other in that one.
Nurses