Absolutly I'd love some Microdugeons and Monsters. A lore would be appreciated,too. Maybe use the draconis race mod explaining which race came from there and what happend to it.

Sure. Perhaps adding gliders and/or giant insects like in Nausicaa would be fitting. Perhaps larger trees that take up the foreground (like redwoods in FU). If you do ruins/dungeons you could also go for a "mining outpost" or "abandoned skimmer" that used to either mine the islands or the gasses from the atmosphere.

Microdungeons and monsters would be great. I'm not so sure about the lore, it depends on the content. It'd be cool if you manage to avoid contradicting other lore sources.

SCP-2399 as a mega Dungeon would be cool, but I'd take a lot of work.
http://www.scp-wiki.net/scp-2399

I have an idea- Near the cores of some of the gas giants, maybe you could find a possible Erchius Mining Storehouse? I think that'd be a cool idea.

Something interesting I thought of recently was the equivalent of sky mangroves, with the tree "roots" growing farther down into the atmosphere.

I think microdungeons would add a lot of life to the planets!It would definitely add to the immersion in terms of it matching up with vanilla, but having more reason to fully explore is certainly welcome. In terms of monsters focusing on airborne creatures could be cool, but also having things that can walk on all sides of a platform like the spiky ball upgrade could be really interesting and would fit the environment well.

I have two dungeon ideas, both of them sky themed.

#1: I got the idea from FU's wrecked space ship dungeons, but the idea I have would be that it would be in broken pieces floating around the area, making it have more of a platforming type of challenge as you try not falling deeper into the planet.
The space station one is basically like the wrecked ship idea, but with the space stations you find in space, kind of like they fell into the gas giant and got torn apart.

#2: Because I think The Ancient Race should have more presence in the universe, so why not have a floating temple inside a gas giant? Again with the platforming idea, especially the under side of the temple.

I would like to see perhaps ancient machines mining stuff on these, they haven't been found because hardly anybody goes deep into a gas giant.

As far as animals, they should be either large and dense enough that the get armor jusr because of their density or large and have massive hit point pools and possibly regeneration but almost no armor (not dense enough for it. both should drop unique drops that will help to reduce the danger of the gas giant planets

Pterta is a species of baloon-like animals, being filled with their poisonous spores and protecting their brakka trees. Pure classic am I suggesting, take it