So I thought of a fictional currency for an alien species where the "money" is actual a form of energy that is stored in the body and can be transferred from one body to another. From a video game design stand-point, it's brilliant because it's an in-universe explain on how the characters are able to carry that much money.
Something that I have noticed when it comes to science fantasy is that is is mostly combining medieval fantasy with space travel or steampunk with space travel. I'm all for a space wuxia or at least an alien civilization that resembles Ancient China or Asia in general.
Speaking of caves, I was thinking about having an alien race that builds everything in hollowed out caves, maybe in cliff-sides (like the Puebloans), or in completely underground caves. They probably might even hollow out asteroids, moons, and dwarf planets to make space stations. So imagine going inside a cave and seeing apartments, hotel rooms, restaurants, stores, etc.
Now for something weird. I have always had dreams of finding stores and restaurants in weird places. In my dream game, I plan on having the in-game stores be corner stores or convenient stores, much like in Earthbound or Pokemon, but given the schizo tech in this science-fantasy universe, you would have basically modernized convenient stores in medieval, old-western, or even pre-historic styled buildings. So there will basically be rustic, wooden buildings with modern beverage fridges inside. You can even have a cave with one room of the cave being a modernized convenience store.
So basically just have old-style buildings with modern (or futuristic) appliances in them.
Star Wars popularized wizards in space. I think we should also have witches in space. We can have alien witches flying between planets on their broom sticks.
Gas Giant planets can have floating islands or even continents in them, kind of like the main setting of Skies of Arcadia.