Geezer pretty much wrote all of Sabbath's lyrics. Ozzy basicly came in and did his thing, but didn't contribute a lot creatively. Though Geezer and Dio I guess co-wrote a lot of the newer lyrics.

Anyway, my list goes as follows:
Mark Sandman - Morphine
Tom Waits
Neil Fallon - Clutch
Les Claypool - Primus
Mike Patton - Faith no More, Mr Bungle, Tomohawk, etc, etc, etc...
Celine Vigil - Seven Year Bitch
Jim Infantino - Jim's Big Ego
Ben Folds - Ben Folds Five, solo