I recently played a small campaing with Cairn and I enjoyed what these systems with a few abilities achieve. Barrow Delver is a nice set of solo rules for it.
Mausritter is a great intro to the “OSR spirit”: due to the player being a mouse, you won’t be a hero for long if you run straight to every dangerous situation. Einzelmaus exists to play it solo.
I can’t pick just one band, however, I clearly remember the first time I listened to
I’m sure there are more if I think for longer.