Since the release of Mojave, macOS requires Metal Supported Graphics Card, Without metal compatibility graphics acceleration is not possible in a Hackintosh with Mojave.
We have already covered an article with Metal Compatible AMD Graphics Cards, My advice here is to purchase AMD Metal Graphics Card instead of NVidia because the war between Apple and Nvidia is not over, there is no or little hope for NVIDIA Web Drivers.
These graphics card listed below are the cheapest because it is not worth to buy an old NVIDIA Graphics Card for Hackintosh that cost more than 70$ bucks In My Opinion.
Dual DVI (Up to 2560×1600) mini-HDMI 1.4a (w/audio (8-channel)) VGA (with included adapter) Dual simultaneous display capable HDCP compliant
NVIDIA GeForce driver Microsoft DirectX 11, OpenGL 4.3
ED 480p HD 720p HD 1080i Full HD 1080p Supported
300-watt power supply recommended 65-watt max power consumption
NVIDIA Adaptive Vertical Sync technology, NVIDIA Unified Architecture, NVIDIA PhysX technology, NVIDIA CUDA technology, Hardware Video Decode Acceleration, Blu-ray 3D ready HDMI xvYCC Color & Deep Color technologies Lossless audio bit stream capable.