Frontier: Elite 2 main theme by David Lowe, Amiga version. It may just be my memories from the game, but that track never fails to pick me up.
Crusader: No Remorse, the entire OST. Industrial meets 90s midi techno.
Ascendancy, OST by Nenad Vugrinec. Awesome ambient sounds.
and the Mass Effect OST.
Firewatch
Well-made story-focused, no combat whatsoever. Very few puzzles, almost exclusively about exploring.
What Remains of Edith Finch
More “puzzley”, but lets you discover things at your own pace.