There two pages might help you with third party mods. But I have to say they aren't really consitent with third party mods, I have a modpack with a few third party mods which are all on the list but it just got rejected 3 times in a row for no reason and I have succesfully uploaded it about 5 times.
Allowed third party mod list:
Submit a new third party mod:
More info about third party mods in your pack: