Besides the obvious candidates catsup (does anyone still spell it that way? I feel like I just put another 20 years on myself) and mustard (by the way, preserves, much like jello, are better cold imho), I'd say society has done a pretty good job of deciding what goes where.
Salsa and nacho cheese (if not cooked) are definitely better cold - not sure if that's standard convention or not, given they get sold in the chip aisle and not the cheese aisle.
Actually, methinks dairy is almost always best cold or cooked (even stinky cheese), but going either way can improve (like gruyere is better cold and swiss is better melted imho) while towing the middle line (room temp) fracks it all up.