It also has an open-source re-implementation of the engine in the works which is currently playable, and a graphical enhancement program which adds distant land

It also has an open-source re-implementation of the engine in the works which is currently playable, and a graphical enhancement program which adds distant land to the game along with some nice optional shader effects like sunrays, depth of field, better water, etc. Also, there's a mod similar to Skywind for the Oblivion version of the engine. Plus there are some enormous mods such as Tamriel Rebuilt, which aims to add the entire province of Vvardenfell, and Skyrim: Home of the Nords, which aims to depict Skyrim during the game's time period. The amount of content that has been made for that game, even beyond normal mods, is kind of staggering.