Librarything says I own and/or have read ten or more books by these authors:

Terrance Dicks (83)
Roger Zelazny (63)
William Shakespeare (46)
Terry Pratchett (43)
Nicholas Briggs (35)
Justin Richards (35)
Brian Aldiss (33)
Neil Gaiman (29)
Ian Rankin (27)
Paul Magrs (24)
Lois McMaster Bujold (22)
Marc Platt (21)
Dr. Seuss (21)
J.R.R. Tolkien (21)
Steve Lyons (20)
Jacqueline Rayner (20)
BBC (19)
Eddie Robson (19)
Jonathan Morris (18)
Paul Cornell (17)
Ursula K. Le Guin (17)
Arthur Charles Clarke (16)
Roald Dahl (16)
Lance Parkin (16)
Gary Russell (16)
Robert Silverberg (16)
Stephen Cole (15)
Simon Guerrier (15)
Bill Willingham (15)
Alan Barnes (14)
Lindsey Davis (14)
David G. Hartwell (14)
Ian McDonald (14)
David A. McIntee (14)
Sheri S. Tepper (14)
Isaac Asimov (13)
Ken MacLeod (13)
Gareth Roberts (13)
Trevor Baxendale (12)
David Bishop (12)
Enid Blyton (12)
Gardner Dozois (12)
Charles Stross (12)
Christopher Bulis (11)
J. K. Rowling (11)
Dave Stone (11)
Iain M. Banks (10)
Colin Brake (10)
Arthur Conan Doyle (10)
Herge (10)
Fritz Leiber (10)
Joseph Lidster (10)
Ian Marter (10)
Lawrence Miles (10)
Kate Orman (10)
Dav Pilkey (10)
Neal Stephenson (10)
Joanna Trollope (10)
Mike Tucker (10)

Many, but not all, of these are Doctor Who writers.

(Including for these purposes the BBC.)