Rendition's Sierra Screamin 3D
Although the company basically only produced two GPUs in the mid- to late-90s, Rendition was a major competitor to 3dfx and Nvidia in its day. Supposedly, Rendition worked directly with id Software's John Carmack to make a hardware-accelerated version of Quake (called vQuake). However, 3dfx also offered its own API-laden version that seemed to have Carmack's signature as well.
The biggest selling point of the company's first entry, the Vérité V1000, was that it offered both 2D and 3D support. 3dfx didn't offer a combo card until later on with the Voodoo 3. Digging the 2D/3D combo, three companies jumped onboard the Vérité V1000 bandwagon: Creative Labs (3D Blaster PCI), Sierra (Screamin' 3D), and Canopus (Total 3D).
Eventually, Carmack set the record straight with regard to who ruled the GPU market, saying that Rendition's 3D accelerator was id's "clear favorite," despite 3dfx's popularity. Indeed, the visuals were simply awesome when compared against 3dfx's GLQuake. Unfortunately, neither company survived the turn of the century.