In an unraised pot this could be anything. I say that because the pot is not going to be very big at the river and a PS bet there doesn’t mean much. It could be any split pair or PP that decided he was gtg and as such bet the pot on the river hoping for a call. It could be a complete bluff and bet big on the river to force a fold and pickup the small pot. Basicaly, do what your gut feel tells you to with these pots because they are small.

In a raised pot this could still be anything but some situations stand out. Like if the flop is KK4. The min bet here usually means they have a K and a reraise will reveal it (but make everyone else fold). You would be surprised how often this works in a multi way pot. Like 4/5 players see the flop of KK4 and one min bets…everyone will call. If they really put the person on a K they would know they are too far behind to call. If I have something here I’ll reraise and if I have a good draw that can beat his trips I’ll call. In any case, the pot size bet on the river means he has something pretty nice and wants some value out of it.