AMD

That really depends on how you consider a GPU. Is it a card that can handle both 2d and 3d acceleration on board (like the S3 virge or the voodoo banshee) or a single chip that can handle both 2d and 3d acceleration (just like the 256)? The latter definition makes the GeForce 256, the very first "GPU", but not the first card that does both 2d and 3d. That can be attributed to a myriad of cards including the ATI rage series, the banshee, the S3 virge and savage, Nvidia's own riva TNT and TNT2, and even matrox g200 series.