Meh, even my old Radeon 6790 did an OK job after you fiddled the settings long enough. It looked semi-potato ofc.
I'm currently using Rx 480, perfectly playable tho I do occasionally get some heavy stuttering and the FPS certainly isn't smooth 60 if that's what you're after. Well, my PC is from 2011 anyhow, so even my lower memory speeds might be part of the issue. I'm upgrading next year.
So I'd say GTX 1660 Ti or maybe RX 5500 (launch Q4 2019, worth checking some comparisons probably)
(The reason my 2 previous GPUs happen to be AMD isn't because I'd be brand loyal, but because 6790 was the better option for my budget and then 480 came out top in bottleneck calculator for my existing hardware. The one I had before those two was GeForce 6200 after all.)