i'm leaning toward pair/flush draw hands as well. why would he risk checking the turn OOP with a hand like KK, QQ when your calling range includes so many worse hands, and given the multitude of draws now possible, shouldnt he be looking to get as much in as possible while he's likely ahead? AT could possibly be c/r'ing turn but again, is unlikely to be raised UTG pf.

small size of turn raise seems to suggest villain is either planning to raise/fold to shove (hands like ak, aq, kq) or has AT,9T and is extracting value/preparing for stacks to enter on river, however i think these are unlikely . given that you smoothed pf and flop, your hand is well hidden, i'd probably ship it. you might even get called by AK, AQ, AA, KQ.