How about the Number Nine Imagine 128 Series II?
https://www.vgamuseum.info/index.php/companie … -imagine-128-ii
Up to 8MB frame buffer and a 250Mhz RAMDAC.
It has rudimentary 3D features, similar to the Millennium, but it's tough to call this a full fledged 3D card since it can't even do texturing and seems unlikely to work at all for most 3D games despite having a basic Direct3D driver.
https://vintage3d.org/n9.php
(Note: The 3D testing on that page is done with the later Revolution card, not the Imagine 128)
I'm not sure how it stacks up to the Millennium or S3 968, but it is probably somewhat competitive... other than in DOS of course, since it uses an old GD5424 for DOS applications.
Even the original Imagine 128 also supports 8MB on some models:
https://www.vgamuseum.info/index.php/companie … ine-imagine-128
Additionally, there are probably some professional cards out there with powerful 2D-only configurations... though they are mostly made long after the 3D era began, so that isn't really what the thread is about.
For example, the XGI Volari Z7\Z9s\Z11 from 2005-2007:
https://www.vgamuseum.info/index.php/companie … -xgi-volari-z9s
Now for some blitting from the back buffer.