I could recommend a free RPG horror game if you like, but Ib and The Witch's House (original version) is a nice game for speedruns, but you'd better run the games you're interested in.
Yep, like what @Tegron said, you need to run games that you're interested in. You'll find it's easier to speed run games you're really invested in. As for games reco, you can try Quake.
