So yes as said, The tracks are from Pokémon Explorers of Sky. Here's the playlist, if ya want it.
1. Night -A New World
2. Eerie (Meteor, Blood Moon) -Growing Anxiety
3. Overworld Day -Do Your Best, as Always!
4. Boss 1 (Eye of Cthulhu, Eater of Worlds, Skeletron, Skeletron Prime, Duke Fishron)...