Authors I own ten books by:

Brian Aldiss
Iain (M) Banks
Lois McMaster Bujold
Arthur C. Clarke
Neil Gaiman
Terry Pratchett
Sherri S Tepper
Roger Zelazny

Other authors I’ve read ten books by (I think):

Piers Anthony
Enid Blyton
Agatha Christie
Patricia Cornwell
Lindsey Davies
Philip K Dick
Robert A Heinlein
Ursula K Le Guin
C.S. Lewis
Larry Niven
Ellis Peters

Slightly surprised that some authors who I rate quite highly haven’t made it (or never made it) to ten books!