Are there any good examples of single player -> MMO that were successful? I loved Fallout and Elder Scrolls but absolutely hated ES:O and FO:76. I loved those

Are there any good examples of single player -> MMO that were successful? I loved Fallout and Elder Scrolls but absolutely hated ES:O and FO:76. I loved those games for having my own little world that was my own. Lack of multiplayer was a feature itself, not something I wanted to be implemented. As with most MMO's I feel like I wanted to play an MMO I'd just mainline WoW, not some crappy imitation reusing IP.