Here are a few Youtube videos that might provide some inspiration for your Cosmic Cutthroats games.
The first is on the scientific and mathematical underpinnings of other dimensions, and the theories behind dimension travel. This is part of why Cutthroats is called a psychedelic RPG … If your PCs are students at the Academia Esoterica or Proto Kyoto Academy, this is what their homework is like.
Here is the Epic of Gilgamesh, sung in (what we think is close to) the original Sumerian. This is a sample of what PCs might hear wandering through the Ziggurat District, the capitol of Uru Ulan.
A couple of more suggestions for in-game tunes. This one is a personal favorite, since it literally is in-game tunes. Something here for every occasion.
Finally, a suitably operatic, epic album perfect for when you want something sweeping and majestic. Closing in for the last battle with that Sanguine Totality anti-paladin warlord? Here you go!
That’s all for now!