PCPartPicker part list:
https://pcpartpicker.com/list/j7vqQZ
Price breakdown by merchant: https://pcpartpicker.com/list/j7vqQZ/by_merchant/
CPU: AMD - Ryzen 5 2600 3.4 GHz 6-Core Processor ($159.99 @ Amazon)
Motherboard: ASRock - B450 GAMING-ITX/AC Mini ITX AM4 Motherboard ($89.99 @ Newegg)
Memory: G.Skill - Ripjaws V Series 16 GB (2 x 8 GB) DDR4-3200 Memory ($114.99 @ Newegg)
Storage: Samsung - 860 Evo 1 TB 2.5" Solid State Drive ($127.99 @ Amazon)
Video Card: EVGA - GeForce GTX 1060 6GB 6 GB GAMING Video Card ($229.89 @ OutletPC)
Power Supply: SeaSonic - FOCUS Gold 550 W 80+ Gold Certified Semi-Modular ATX Power Supply ($69.90 @ Amazon)
Total: $792.75
Prices include shipping, taxes, and discounts when available
Generated by PCPartPicker 2018-11-18 22:44 EST-0500
I gave you a 1060 but with your budget you could easily do a mini GTX 1080. Also didnt give you a case but any ITX or small mATX would work.