Physically any current graphics card would work. What's best for a balanced system (for gaming) would depend on your CPU. So what are the rest of your specs and likely budget?
EDIT: What sort of games? Screen resolution and refresh rate?
Here's the rest of the stuff
CPU: Intel Core i7-7700 3.6 GHz Quad-Core Processor
CPU Cooler: Cooler Master Hyper 212 Black Edition 42 CFM CPU Cooler
Motherboard: ASRock Fatal1ty H270 Performance ATX LGA1151 Motherboard
Memory: Kingston HyperX Predator Black 16GB(2 x 8 GB) DDR4-2400 Memory
Storage: Samsung 970 Evo 1 TB M.2-2280 NVME Solid State Drive
Storage: Western Digital Caviar Blue 1 TB 3.5" 7200RPM Internal Hard Drive
Case: Phanteks Eclipse P360X ATX Mid Tower Case
Power Supply: Silverstone 600 W 80+ Gold Certified Fully Modular SFX Power Supply
Case Fan: Cooler Master MasterFan Pro 140 Air Flow RGB 53 CFM 140 mm Fan
Case Fan: Cooler Master MasterFan MF120R ARGB 59 CFM 120 mm Fan
Case Fan: Cooler Master MasterFan Pro 140 Air Flow RGB 3 in 1 with RGB LED Controller 53 CFM 140 mm Fans
As for budget, probably around $1700 - 2000
Edit: forgot to add that some of the parts maybe changed (cept for cpu, case, and mobo though)