So, I settled for the swamp village (yay!) aaand I will include a kind of wyvern's lair in the package (like a mini cavern)
I doodled as a guideline some things I'd like to include in my swamps, from references and imagination :
So you can see little houses, wood structures, boats, creatures, rocks and vegetation with twisted-roots-trees (and a mini wyvern in the middle).. I'm not sure all of these can fit in 50k, but I will try! The reference style is really low poly, so it could work out.
As you can see on the little scene doodle, I'd like to go with three 'zones' : - a village / - a loner house (maybe shaman's place or something) / - the monster's cavern.
Here's my early starting point :