The mid range tier cards:
- GTX 1660 - speculating for it to be slightly better than the GTX 1060, putting it around RX 590 tier or close to it, comes out later next month, but not worth upgrading from a 970.
- GTX 1660 Ti - speculating for it to be around GTX 1070 tier or close to it, rumored to come out in 2 weeks (February 22nd).
- RTX 2060 - GTX 1070 Ti tier.
These 3 have 6GB of VRAM, I could see that maybe becoming an issue even at 1440p in the future, but for 1080p I don't think it'll be a problem anytime soon.