For what version? I'm working on a modpack myself that I'll be releasing soon, it's based off the old Hexxit modpack and is for 1.7.10 (because imo 1.7.10 has the better mods for bosses and such). It won't be a random mash-up of mods either, I picked each one for a purpose, and got rid of any crashes/id conflicts that they have. I am in the process of adding quests right now, just have to get school-work out of the way lol.
If your wanting one for a more recent version I don't really know, I do know that a mod called "Magic Kingdoms mod" on curse just came out for 1.12.2, by itself it seems to add a lot of nice RPG-type elements, should give it a shot.
Well I was more looking for 1.12.2, but I guess any version works for an RPG like modpack, and i had no idea that version exactly was the best for modding