suggesion Ideas for outer cluster worlds

[MiniDeathStar]

At the moment we have a rich variety of inner cluster worlds, but all of them use the same outer planetoids: water, dust, ice, isoresin, lava and moo.

To add some variety and challenge, here are some more ideas for distant planets:

• Gas giant: A large, frigid planet that consists of highly compressed liquid hydrogen, a mantle of water ice and frozen methane, and a small rock/iron core. In real life, most gas giants are very hot on the inside, but some like Uranus are extremely cold. There is a challenge of working safely in the environment without disturbing the pressurised H2, which can flood the base and become lost to space.
• Comet: A small asteroid that's predominantly regolith and water ice. There are a few hot steam vents on it, which simulate outgassing under stellar radiation.
• Extinct world: Aeons ago, there used to be rich biosphere on this world, but a mass extinction event has turned it all into coal, fossil and oil. The surface consists of a radioactive impact site and lifeless barrens, but if one digs deeper they may find the odd specimen miraculously preserved in amber (resin).
• Cauldron: A small arid sulfurous world, ravaged by volcanoes and tidal friction. Inspired by Jupiter's moon Io.
• Black dwarf: An extremely ancient stellar core that has since cooled into a dead remnant. It consists of impenetrable spires of neutronium, intersperced by diamond, graphite, and heavy metals.
• Derelict station: A ruined gravitas facility that has experienced a major radioactive catastrophy. Most equipment is melted into lumps of corium and lakes of nuclear waste. Ambient radiation is extremely high.
• Toxic world: Underground oceans of caustic chlorine chew their way through a porous bedrock of lime. The core traps a pressurised pocket of sour gas, which is constantly churned out by several geoactive vents.

Of course, if you (the community) have any more ideas, you're more than welcome to share as well!