There aren't too many cards listed on the official supported list, but I'm wondering if any of the older nVidia cards like Tesla M2070Q/M2090 or the Quadro 4000 cards are still working for people using vSGA or vGPU on ESXi 6.5??
Eg there are 5.1 host drivers here: NVIDIA DRIVERS 304.76 supporting more cards than the 6.5 drivers