You'll need either the 7000 PCI or 9200 PCI Mac edition. You also have a possibility of flashing the 9250 LE non-Mac version, but the compatibility of these seems questionable.
Are you wanting to use OS X or System 7/8/9? The flashed cards don't appear to work flawlessly in System 7/8/9 unless you get a specific model number of a Connect3D 9250 (of which there don't appear to be any left).
If it's for OS X, then there's the option of the much more powerful Geforce 6600 PCI flashed from PC to Mac; as a bonus it seems to support both core image and quartx extreme.
Lots of info on Cubeowner.com
(I'm looking for a 9200 Mac edition, too, for a Biege G3 I'm putting together for Mac OS 9)