Sometimes there's a mod that you just can't find on CurseForge, what do you do?
It's entirely up to the author of a mod to upload it to CurseForge, however, if the mod is hosted publicly, has a proper license that allows us to distribute the mod, and you can provide us that information we're happy to add it to our Approved Non-CurseForge Mods list.
We recommend first checking the list to make sure the mod you wish to add isn't already on there, and if not you ca submit a request. It can take several days for a review to occur.