It is likely most of the times either AK, sometimes also 66/99 and A6/A9/AA/22
But AQ is imo too strong to fold on the river
Players would likely not 3-barrel bluff too many times or play AJ/AT that way
But they can shove up busted draws enough times to call him down
I could also consider shoving turn myself, since you´re not folding blank river and he would b/c with draws