On the river IP when facing a check when you have what you believe is for sure the best hand, and villain has a hand that he likely can't fold, but also probably won't c/r a regular sized bet.

Maybe if you have like AQ on KJTx9 board or something. Or you have KK on J53KJ board. In both spots if you're tripling and villain is c/c down then I don't expect villain to c/r rivers too often vs your tripling range, but lots of ppl will have trouble folding nut'ish hands (straight in first example, or Jx in second example) even to an overbet.

Or in spots where villain's range is capped. You are OOP on 742hh board and PFR checks back IP, turn is Th you lead turn, river is some brick, could be a good spot to over-bet because PFR rarely has a strong hand or flush after checking back flop. Spots like that. Some ppl might hero call you though because they KNOW they don't have flushes.