Dragon Lance, Death Knights of Krynn, because Lord Soth is my favorite AD&D character.
Ravenloft , Strahd's possession and Stone Prophet ,you could transfur characters between games.
Darksun 1 and 2 sorta had an open world but in a D&D style.
Eye of The Beholder , Eye of the Beholder II The Legend of Darkmoon, Eye of the Beholder III: Assault on Myth Drannor because i painted that skeleton on the cover on my wall in my room as a kid lol.
There was a game on Sega Genesis, called Warriors of the Eternal Sun, which im not sure if their was a PC version made.
Pretty sure most of these games were made by SSI, Strategic Simulations,INC.