praeter

praeter takes the ACCUSATIVE, always. Its physical sense is "past, alongside", from prae, and everything else grows out of that: what you walk past you leave out, so "past" becomes "except", and what goes beyond a limit is "besides" or "more than".

The case rule catches people out in the "except" sense. The excepted word goes accusative whatever job it would otherwise have done, so "everyone except one man came" is omnes praeter unum venerunt, with unum accusative even though the man in question is one of the subjects. The family around it is large and useful: praeterea "besides", praeterire "to pass over", praeteritus "past", which is where the grammatical term comes from.