Happy Days (Joanie Loves Chachi / Mork and Mindy / Laverne and Shirley)
Friends (Joey)
The Mary Tyler Moore Show (Rhoda / Lou Grant / Phyllis)
Buffy the Vampire Slayer (Angel)
Tha Man From UNCLE (The Girl From UNCLE)
Casualty (Holby City)
Law and Order (Trial By Jury)
No Hiding Place (Echo Four Two)
The Six Million Dollar Man (The Bionic Woman)
Porridge (Going Straight)
Dynasty (The Colbys / Falcon Crest)
Another World (Somerset, aka This Is Somerset)*
Cheyenne (Bronco)
Soap (Benson)
Coronation Street (Pardon the Expression)
The Dukes of Hazzard (Enos)
Bewitched (Tabitha)
Cheers (Frasier)
Upstairs Downstairs (Thomas and Sarah)
Danger Man (Secret Agent / The Prisoner)
Heartbeat (The Royal)
Diff'rent Strokes (Hello Larry / The Facts of Life)
Cannon (Barnaby Jones)
Sanford and Son (Grady / The Sanford Arms)
Man About the House (Robin's Nest / George and Mildred)**
Babylon 5 (Crusade)
Trackdown (Wanted, Dead or Alive)
Phoenix Nights (Max and Paddy)
The Bill (MIT / Burnside)
Star Trek (The Next Generation / Deep Space Nine / Voyager / Enterprise)
Golden Girls (The Golden Palace / Empty Nest)
All In The Family (Maude / The Jeffersons / Gloria / Archie Bunker's Place)
M*A*S*H. (AfterM*A*S*H / Trapper John MD)
The Cosby Show (A Different World)
Home Improvement (Buddies)
Please Sir! (The Fenn Street Gang)
Beavis and Butthead (Daria)
Dallas (Knots Landing)
*The first soap opera spin-off (c1970)
**The US version of this show Three's Company had a spin-off called The Ropers, in which the Ropers were called Stanley and Helen, not George and Mildred)
Two spin-offs which thankfully didn't happen: K9 and Company (Doctor Who) and a series with Manuel from Fawlty Towers