If the mod is available on curseforge you can request it.
But requesting it isn't enough!! Once I added 5 more mods to FTB Sky Factory 3 and when I went to add the mods to forge so that I can add extra mods, I did not get A LOT of mods, so it is very time consuming to request all the mods.... Probably adding all the mods in the forge mod list for a modpack is better....
Something like this would really change the customization users will be able to do with their modpacks...