[Finalgenesis]

Most of the lone or multi single figure target damage spells (bolts, darts, even star fire ...etc) can be parried I believe, those with AoE such as acid bolt are not subject to this of course. and of course, arrows, bolts, magical or otherwise can all be parried, though magical projectiles receives a +2 hit check (I assume a buckler with 2 parry will be almost useless against magical projectiles).

I read that Androphage arrow with its poison arrow is an exception, as is Piercer Xbow from 1st hand testing likely as a unique attribute of the weapon, I have not tested vision Foe, but I know ethereal bow can be parried.