Vanilla Skyrim has dozens of quests, but the community's quest mods rival official DLC. Legacy of the Dragonborn is a museum-hub that ties your whole playthrough together, VIGILANT is a Dark Souls-inspired descent, and The Forgotten City won awards as a standalone. These add tens of hours of genuinely better-written content than the base game's side quests.
Ranked by hand, not auto-generated. Every mod links to its full page with install guide + compatibility.