We often use except and except for as prepositions to mean ‘not including’ or ‘excluding’. They are followed by a noun or noun phrase or a wh-clause. Both except and except for are correct after a noun:
I like all fruit except (for) oranges. (excluding oranges)
Except for Louisa, who’s away in Berlin this weekend, we’ll all be at the party.
She likes going to most sports events, except cricket matches.
Except can also be used as a conjunction. We don’t use except for in this way:
The brothers are very alike, except (that) Mark is slightly taller than Kevin.
Except and except for are used in similar ways to apart and apart from.