These are designed as resources for GM's who want to quickly generate worlds. They are designed to only require the core book for the game. They are in Google Docs. Just Ctrl-R to generate new world.
Traveller (Mongoose Games) World Generation
Space Opera Basic Role Playing World Generation
(For Chaosium's Basic RolePlaying System)
In accordance with Space Opera, most inhabited worlds are fairly Earth-like, but often contain strange inhabitants.
Mutants & Masterminds World Generation
This generates worlds with a comic book sensibility. Most worlds are inhabited by humanoids.
High Fantasy Land Generation (BRP)
Creates fantasy lands/kingdoms etc. for Basic Role Playing
General Template for World Generation
Astronomy: Solar Luminosity, Distance from Sun, Year Length
Planetology: Planet Size, Satellites, Rotation Period, Axial Tilt
Fluids: Atmosphere, Temperature, Fluid Coverage
Biology: Native Life
Technology: Tech Level
Demography: Population Size
Politics: Planetary Unity, Government tupes, important and excluded groups
Economics: Imports & Exports
The details vary with the background. Imports & exports matter in Traveller but aren't going to be a concern a superhero setting.
Rare Earth Hypothesis
My spreadsheets, basically follow the Weak Rare Earth Hypothesis, in that really Earth-like worlds are rare, but marginal worlds are far more common. In Space Opera settings, Earth-like worlds are often assumed, but there are probably many uninhabited, uninteresting worlds.