I'm only listing the ones I can definitely verify on my book list, which is extremely patchy before '02 or so. On the other hand, there are writers on this list I know I haven't read since '02.
Marion Zimmer Bradley
Lois McMaster Bujold
Orson Scott Card
Charles de Lint
Neil Gaiman, if you're counting the Sandman graphic novels as books
Robin Hobb, if she and Megan Lindholm count as the same person
Diana Wynne Jones
Maud Hart Lovelace
Kim Stanley Robinson
I suspect James Morrow, for example, but can't verify it without digging around counting books in his bibliography, and I don't want to do that. I expect Peter O'Donnell will go over the mark next week.