Since the list in the first post had grown too large, I've reorganized it and limited to only downloadable content for PC versions, since console version differences are often too numerous and might deserve a separate thread (maybe even for each game). The extra content from consoles that was converted to the PC format and is downloadable is still listed though.
I've also added more download links, the info about the
Star Wars: Jedi Knight II: Jedi Outcast demo, and the rare
Age of Empires Computer Gaming World magazine demo.