The ambience in this game is amazing, but theres a lot of little small things that could make it a lot better too- so heres just some ideas i had in mind!
1: Morning Dove and Other Birds: The morning dove just gives off such intense nostalgia for almost everyone im really suprised its not in the game- in some biomes when it turns morning a morning dove can be heard in the distance- this could play in forest biomes and the ||frutiger aero|| inspired ones
other birds like seagulls near shorelines, crows, and owls at night could be really nice too
2: Crashing waves: Near shorelines, faint wave sounds could be heard intensifying as you get closer. Perhaps at certain times of the day theyre stronger or weaker, this could be paired with the seagulls too to add a calming atmosphere around the already generally atmospheric coasts
3: Droning and buzzing near lights: Light blocks could emit a faint buzzing noise similar to the noise a lot of fluorescent lights make in some buildings