Tough call, but i would call, the hands range u beat is big but it looks like he hit the flop hard, so its either a set or 2 pairs, he would definitly not limp in with Q6 or Q7, so he can hold pocket 7, 67s or maybe a flush draw.

set

you should've thought about what you'd do if he shoved before you 3bet the flop, because it's very rare he's just gonna flat that raise. he's mostly gonna be shoving or folding which makes your hand a bluff if you intend to fold to a shove. always plan ahead what you'll do before you make your move. options here are calling his raise on flop and putting in a check raise on a clean turn or improving turn and folding to a scare card (mainly a diamond obv), getting it in on the flop or folding to his initial flop reraise. so basically the point at which you decide what to do in the hand is when he raises you on the flop, think about what his range is and play accordingly (if it's only sets then fold to that raise, if he has a shitload of flush draws then call and try to get it all in on the turn or get it all in on the flop). if he's a pretty aggressive player he can have combo draws/76/sets/MAYBE even a limped AA. QQ is unlikely so that can probably be discounted.

Board: 6c Qd 7d
Dead:

equity win tie pots won pots tied
Hand 0: 32.915% 32.91% 00.00% 2281 0.00 { Qs6s }
Hand 1: 67.085% 67.09% 00.00% 4649 0.00 { 77-66, 9d8d, 76s, 5d4d }

You're 33% vs 76/77/66/OESFDs

that's a pretty tight range though, although some people may be even tighter and play the OESFDs slow, slowplay the sets and so on, so it just depends what you think the player is capable of. Some people could have a far wider ride including 6dAd, 6d5d, 8d9d, maybe even a limped AA and against that range you're around 50/50 or so.

THIS is 100% fold(unless you have a uber read), oesd is 90% call 3b from my experience. I would fold this since it is an unraise pot. Only hand i see you being ahead of is AA,KK and he still has 30% to catch.