Since I've recently stumbled upon some I didn't know about I thought I'd just make a list of the ones I've found in various states of completion, let me know if I missed any! A couple of these rely on forks of ResidualVM or the discontinued ScummVMExt fork.
Remastered Soundtracks by The Fat Man and Team Fat (ScummVM-compatible music sets by the original composer of several supported games, including instructions on how to hear the remastered music while playing.): https://thefatmanandteamfat.bandcamp.com/
This is the only download I could find of ScummVMExt, https://www.dropbox.com/scl/fi/dl2xd6ls ... 09-x64.zip (I don't know what the latest version was, archive.org's github snapshot only shows ScummVMExt v1.1.179b from 09/08/21)
There's also:
- Might and Magic Book One: It provides an optional enhanced mode bringing in the user interface of World of Xeen (Xeen data files required) and the fan enhanced graphics pack.
- Ultima VI: Offers enhanced mode allowing for full screen world view rather than the small window the original has, container gimps, and a bunch of other enhancements.
I haven't tried it myself, but The Fat Man and Team Fat have released some of the Humongous Entertainment soundtracks on Bandcamp, and they supposedly contain ScummVM compatible versions too: https://thefatmanandteamfat.bandcamp.com/