I love this interaction between the community and the devs, it just is great to see people shoot their unique ideas for this game. I myself, have been planning on getting the world builder, and have come up with several worlds I would love to see.
Reclamation Lands: These are worlds with many deterioration unnatural structures. They range from rotting cities, or unnaturally shaped landmarks. Nature can play a part on them, making them prone to sudden collapses and dead ends. They can also be a home to a cast of spooky gremlins and monsters.
Glowing Jungle: These ancient worlds are home to wonders displays of bio-luminescence, in both the plants and animals. The flora and fauna blink, flash and can even disorient would be attackers with their displays. Being a jungle, however, their is still a steady supply of enemies under the canopy.
Oortian Worlds: (this is a revision on my part of the technology biomes suggested above) The Oortian's Empire linked together hundreds of worlds, spanning the void of space the the Portals. Leftover from their age, are the Observers. They were created to keep particular worlds cleansed of invasive flora and fauna. However, many of these Observers' worlds have become corrupted, turing the world into a stormy wasteland.
Pure Oortian World:
Corrupt Oortian World:
Thats it for now. Feel free to give some feed back if you enjoyed!