And in a similar way, Robin’s Nest was a spin-off of Man About the House and in America Three’s A Crowd was a spin-off of Three’s Company.
So, we get to mention the Detective John Munch multi-verse already. Cool. L&O for the win!
Doctor Who has them all beat. There have been 12 (13?) separate incarnations of the Doctor. 
Also at least a couple of animated shows.
- Laverne & Shirley in the Army
- Fonz & the Happy Days Gang.
Well, the richie cunningham character did first appear in love american style
Episode 70, Feb 1972
“Love and the Happy Days”: An American family of the 1950s gets their first television; teenage son Richie and his friend Potsie assume it can be used as a chick magnet.
And Richie and Potsie went to “Happy Days” intact, so thats kind of a spin off?
But all of them have been within one TV series, which has carried the same name throughout.
The Archie Show (1968) spun off 10.
Sabrina and the Groovie Goolies (1970)
Groovie Goolies (1971)
Sabrina the Teenage Witch (1971–1974)
Archie’s TV Funnies (1971)
The U.S. of Archie (1974–1976)
The New Archie and Sabrina Hour (1977)
Sabrina, Superwitch (1977)
Groovie Goolies and Friends (1978)
The New Archies (1987–1988)
Archie’s Weird Mysteries (1999–2000)
Yeah, I didn’t think that would fly. How about:
[ol]
[li]K-9 and Company[/li][li]Doctor Who Confidential (documentary series)[/li][li]Torchwood[/li][li]Torchwood: Children of Earth (miniseries of the above)[/li][li]Sarah Jane Adventures[/li][li]Dreamland[/li][li]Class (being developed)[/li][/ol]
They both also spun-off shows about the landlords - George and Mildred for Man About the House, The Ropers for Three’s Company. Which is actually another interesting question - is there another time this has happened? A foreign remake spinning off remakes of the spinoffs of the original series, I mean. (And has the reverse ever happened? That is Domestic show A gets a foreign remake B. B gets a spinoff C, and the makers of A remake C as A-spinoff D.)
Actually, Class has already broadcast 8 episodes (just not in the States yet).
A lot of people have chimed in, and so I guess MTM doesn’t have the “spinoff record.” But one thing I was amazed about when I recently saw the original MTM episode is how many of the cast went on to be the main star of a subsequent successful show within a few years of being on MTM–basically the whole cast: Harper, Leachman, Asner, Knight, White and Stevenson.
As in “McLean”? 
Maybe you’re thinking of Gavin MacLeod? :dubious:
Yes, Macleod. Thanks.
While he wasn’t a regular, you might also add John Amos, who had a recurring role as Gordy the weatherman, to that list.
The Betty White Show lasted a whopping 14 episodes. She appeared more times as a guest star on Mama’s Family. She’s been successful, but not right after MTM. It wasn’t until Golden Girls 8 years later that she was a regular in a successful series but then as part of ensemble, not the lead. (If any GG was the lead it would have been Bea Arthur.)
Her other successful show was Hot in Cleveland but again in an ensemble.
Happy Days had three spin offs.
Laverne and Shirley
Mork and Mindy
Joanie Loves Chachi
One of the aspects of The Golden Girls that I liked was how Betty White and Rue McClanahan played against type.
Prior to TGG Rue McClanahan was best known as Vivian Harmon, Maude’s best friend on Maude. Vivian was naive and soft spoken, but on TGG she played Blanche Devereaux a highly sexual and risqué woman.
Prior to TGG Betty White’s best known character was Sue Ann Nivens from The Mary Tyler Moore Show. Sue Ann was highly sexual and risqué, but on TGG she played Rose Nylund a naive and soft spoken woman.
Mary Tyler Moore spun off very established characters.
Laverne & Shirley and Mork only appeared on Happy Days one time. But they both got their own shows.
The Australian comedy We Can Be Heroes: Finding The Australian of the Year had Ja’ime King, the horrific schoolgirl, as one of its feature characters.
She became on of the leads on Summer Heights High, which also introduced Jonah Takaleua as another lead, and continued in Ja’mie: Private School Girl.
Jonah got his own show - Jonah from Tonga.
Only three spin-offs, but a lot for an Australian show,