Before Skyrim, Oblivion, and Morrowind there was Daggerfall, the second entry in what has become a household name for fantasy RPGs. The original is available on Steam and GOG, though 23 years later we have a modern remake in the form of Daggerfall Unity which brings in modern graphics, controls, QoL improvements and mod support (as well as Linux and Mac support).
Unity games can't be compiled and played using free software.
True, but it's not like they were trying to get it added to get GNU project, it does still require the original closed-source game for assets anyway