Jody reviewed the Skyrim total conversion mod Enderal back in August 2016, and liked it quite a bit. It wasn't enough to make Bethesda sweat, but he found it big and beefy, with a high quality of writing and better voice acting than you usually see in fan projects. A Steam page appeared last year, promising to eliminate the hassles involved with installing the mod, and today the developers announced that it will go live on February 14.
Like Skyrim, Enderal is an open world game, but with its own lore and landscapes, completely separate from The Elder Scrolls series. Gameplay has been "overhauled" with new classes, survival mechanics, and "challenging combat," and the Forgotten Stories version on Steam has been expanded with two new "crafting classes," 12 additional side quests and non-linear guild questlines, reworked crafting and spells, and improved performance and stability.
Possibly the biggest attraction is that the Steam release vastly simplifies the process of installing the thing. The original mod had to be downloaded and installed overtop of Skyrim, which is both a little daunting and not terribly convenient if you also want to continue playing Skyrim. Enderal: Forgotten Stories is entirely standalone. As long as you own either Skyrim Classic or Skyrim Legendary Edition—it doesn't have to be installed—you can install and play Enderal.
Unfortunately, it does not work with Skyrim Special Edition; the developers said they might be able to port it at some point in the future, but they don't have the resources to do it now.
Skyrim mods: Questing forever
Skyrim Special Edition mods: Special effects
Skyrim console commands: Endless possibilities