Enderal, a total conversion mod for Skyrim. Free, just requires ownership of the skyrim base game or special edition (has a version for either).

Has a whole new map, reworked classes, changes to combat, banger OST (here’s my favorite, hits incredibly hard when you’re listening to it in-game at a tavern) and the story is jsut incredible. I still think about it, and the choices I made, years later.