Terraria — Full Soundtrack for Building & Focus

Scott Lloyd Shelly wrote the original Terraria music, later expanded by TheXenonPhenom, under an extreme constraint: a player might spend nine hours in one biome. So the themes are short, harmonically simple and built to loop without accumulating fatigue — "Overworld Day" is four chords and a flute line, and it survives being heard four hundred times, which is genuinely difficult to write.

That makes it an unusually good work soundtrack for exactly the same reason. Base-building games tend to produce the best focus music in the medium — Stardew Valley sits in the same pocket — because their scores were engineered against boredom rather than for drama. The cavern and underground themes are the calmer half if the overworld reads as too cheerful for the task at hand.