Out in the wilds far from the bright centre of civilisation, worlds are sparsely populated. But it's always possible to find some settlements even out here - small groups of people who have fled civilisation looking for their own place to live, where they won't be bothered by anyone else.
Sometimes these small colonies die, sometimes they struggle on, and sometimes they thrive.
Deliberate settlements originally designed to colonise a world. They are no longer connected with their original home world, so are completely independent.
Over a hundred years ago, a group of colonists set down on this world to start a new civilisation of their own. However, over the generations they have struggled to keep things going. Though they haven't collapsed, they haven't made much progress, and are finding it difficult to keep their technology base working.
Population is likely in the thousands or tens of thousands. It hasn't reduced, but it also hasn't really been growing for a while.
TL is between 4 and 5, depending on how badly they are doing.
A failed colony is on the verge of collapse, or has collapsed. It's population may have been in the tens of thousands, or even larger, but now is down to a few thousand. Settlements have been abandoned, technology has been lost, and structured government has descended into bickering tribes.
TL is 4, maybe even 3. There will be abandoned ruins, and most knowledge has been lost.
A large colony which was started centuries ago and is now a thriving civilisation of hundreds of thousands, spread out across the world. Mostly still rural, but with some urban population centres with limited industrial capacity.
TL will be at least 5, probably 6.
These are large scale civilisations which have collapsed. At one point they had populations in the hundreds of millions, but have since fallen.
Still a large population, but lots of in-fighting which makes cooperation impossible. People scavenge in the ruins, farming where they can and avoiding violent gangs.
TL is about 3-4.
Small populations living in the ruin of a much older, larger civilisation which has long since fallen. Individual population centres aren't big enough to support technology.
TL is 3.
Groups started by accident, or who just never planned to really colonise.
Small farmsteads, spread out across the world.
Small bands what have never settled down. May have been from a crashed spacecraft.
Just ruins, no sign of the people that built them.
Old research post that has been forgotten about. Only a few remain here.