Possible TTRPG Concepts/Settings

Things that I've had ideas for for a while, and they would translate into a TTRPG really well:

- "Silver Tide," a fantasy world taking place during an event based on the Golden Age of Piracy. Water travel is very prominent. Most creatures and magic are based on things from sailor folklore.

- "Sundown," a fantasy world that takes place in a wartorn nation based on what is essentially a hybrid between post-Civil War United States and feudal Japan. So samurai cowboys with katanas and revolvers.

Ones that I've recently thought of for the sole purpose of this project:

- A sci-fi-fantasy world where musical instruments are used as weapons, making skilled musicians = powerful warriors. Also, "spells" are replaced with "lyrics," and are also not limited to a mage/sorcerer/warlock class. This is my personal favorite idea. ;)

- A sci-fi that takes place in the hypothetical future of our own world. It would be pretty much a generic sci-fi with aliens and robots and stuff, so nothing that special, but I thought I'd share it anyway.

- A fantasy world based on post-Civil War United States. It's like Sundown, but without Japanese stuff. We could even just cut the whole "fantasy world" thing and just make it straight-up take place in the United States during the late 1800s. There'd still be fantasy stuff like magic and monsters, of course, just not a fantasy *world*, per se.

- A sci-fi-fantasy world that takes place on an arid desert planet where where huge steampunk ruins lie underground. As an enemy mothership approaches, the internal planetary defense mechanism that was built by the ancient steampunks must be woken up to defend the planet, since the modern locals don't have the technology to defend themselves against an intergalactic rival.

- A fantasy world with a culture based around the Aztec empire. I don't have much to say about this one, but consider it fairly anyway. Have you *seen* an Aztec sword? 10/10 way cooler than katanas.

- Any more ideas? Suggestions for the ideas I already have above? It might be a lot to sift through, but oh well. We need lots of ideas to make sure we fine-tune this project as much as possible.