Your question should be "What are good GPU matches for my i7 6700K at 1440p gaming? Still we do not know the games involved (AAA titles, esport, a mix) and the graphic settings.
Is not the same to play esport game with performance settings than go with something like CBP 2077 with very high or ultra graphic settings.
In any case, I agree that Radeon RX 5700XT/6700XT or the Geforce RTX 3060/3060ti/3070 are good choices. It will depend on your freesync monitor compatibility too.
Depending on what you choose (GPU wise) and what you play, you mind find that the GPU is been limited by the CPU in some scenarios, or maybe not, is really, really hard to forsee.