Need help coming up with breif descriptions for planets in a homebrew sci-fi setting! gas city indiana police department

One thing you might try is coming up with a list of which species are dominant civilizations in your space, and then come up with a listing of what kinds of planets each one might dominate on. So when you generate a drow world, you have a few parameters for like, what kinds of worlds Drow tend to be the dominant culture on and how that differs from the Gnomeworld and the home planet of the Ghoran, and then you can pick from there and explore down a tree of options, and there you go.

Is the world’s population/industrial base growing, stable, or declining? A growing world will have people running up against the natural limits of the planet, a declining world will have infrastructure not being maintained and need to import things it used to make, and a steady-state world will have issues with stagnation, with its systems running up against their own internal limits, and with the fact that trying to grow means, by necessity, choking someone else out.

Every question here I’m trying to make lead into a problem, by design. When I say "problem", think "a developing situation into which adventurers can make money by inserting themselves". In general, for every question you answer to work your way down a planet design tree, try to create at least one problem, and to avoid planets feeling samey, even if you answer the same questions the same way for them, create different problems.

Is the population small or large? A small population will need to import most of its advanced technology because the infrastructure to produce it won’t be there; a large population gets into the problems of cities and stuff. Who does it trade with? What does it trade?

What’s the planet’s geopolitical setup? One global government? Two competing superpowers, with or without a host of minor powers (a la cold war era earth)? A single global empire? A host of petty states? No centralized government at all? How is this government structured? A federal republic is different from a direct democracy is different from a feudal monarchy is different from an absolute monarchy is different from a bureaucratic dictatorship or a polity that runs as a company town. Whichever combination you pick, write a problem or two.

Then you can get into astropolitics: Are any of the polities (countries, governments, empires, alliances) on the planet arms of an interplanetary empire? An interstellar one? Are multiple polities here arms of different interstellar polities? How does this affect the geopolitical dynamics? How does this planet relate to its larger body; how does it benefit the larger body and how does the larger body benefit it (or was it inducted at the point of a gun)? How much control does it have over the larger body and how much control does the larger body exercise over it?

These questions are vague and don’t directly suggest problems, because the kinds of problems had by, say, the dominant member of a polity that has holdings in 12 systems are going to be different for the headquarters territory of an interstellar corporation, the populous industrial center of a semi-utopian interstellar direct democracy, and the seat of an interstellar feudal empire; similarly, a declining post-industrial world barely sustained by an interstellar direct democracy (which the majority of other members of would like to depopulate but don’t want to handle the humanitarian crisis of simply withdrawing support) is going to look different and have different problems than a company town being downsized

Then you can get into questions of biome (with this many planets, you’ll probably fall back on the single-biome-planet trope) and similar aesthetic stuff like what color the foliage is. You have stuff in your OP about a bunch of different aesthetics, so when you’re coming up with stuff about a given planet, like, a city planet is going to look different if it looks like, say, Blade Runner than if it looks like Coruscant.

Probably also come up with what the most magically-significant site on the planet is and what it does, and maybe a few more if all of them attract interplanetary/interstellar visitors. Depending on how mythic you want to go, some of these places might be, like, the actual literal homes of specific deities (rather than living on the outer planes, Heironeous or whoever lives on such-and-such moon and you could physically land your spaceship there if He lets you)

If you have everything from 3.5 and Pathfinder in, I’d suggest picking one splatbook here per planet and putting its stuff in to put a place for everything in the setting while giving each one its place to shine. So you might have Occult Adventures world, Tome of Battle-world, Expanded Psionics Handbook world, maybe Epic and Mythic worlds, three separate worlds for the Tome of Magic (Truenamer World, Binder World, Shadowcaster World), Incarnum world, Complete Arcane World (home of the Warlocks), Heroes of Horror World (unless you split this into Halloween World (Dread Necromancer) and Eldritch World with the Archivist). If a class from another splat looks like it’d go well with a world, you can rearrange (maybe Eldritch World has Archivists and Binders and CArc’s Alienists and Warlocks, and Arcane World has Beguilers, Duskblades, and Dread Necromancers). So then you have some classes who can come from anywhere (most of the core classes), and then a bunch of other classes which are strongly suggestive of a character’s homeworld. "Another dome city planet" is gonna be more different if one has Truenamers and the other has Incarnum than if one is ice domes and the other is underwater domes.

For more questions to look at, there’s a series of posts about a randomly generated astrogation map based on the original Traveller rules. The most interesting analysis is in the third post, but the second provides context and some questions to ask to make worlds less samey on that level.

The trick to not making things samey is one, to open vastly more space with your generation procedure than you’re gonna use, and two, to use it as a jumping-off point for your creativity. Cranking the generator (especially a random one) is a start. Interpreting your results is an art.