VMware vSphere 6.5U1 and up officially support several GPUs for VMware Horizon 7 environments:
NVIDIA Tesla M6 / M10 / M60
NVIDIA Tesla P4 / P6 / P40 / P100
AMD FirePro S7100X / S7150 / S7150X2
Intel Iris Pro Graphics P580

More information on GPU support can be found in the online VMware Compatibility Guide.

The NVIDIA website contains a listing of GRID certified servers and the maximum number of GPUs supported inside a single server.

Server hardware vendor websites also contain more detailed information on the GPU brands and models supported.