Here's a list of planet mods...they won't be compatible with DS but if you're interested in adding new planets to your own mod, then there's a bunch of different mods you can pull textures and meshes from...
Incorporating those into any personal mod of yours will require some work and I suggest you use a guide (like the Weebly) to make sure you don't forget any steps...
DS has some "add-ons" that are compatible with it (check the DS thread) such as graphics mods or music, but mods in general do not easily stack well...extensive mods, especially any of those that add content instead of simply changing it, make changes to what I guess you could call "universal" game files...
If my mod changes entity file ABC and your mod changes entity file XYZ, then there'll be no problem merging to the two mods...
But if my mod changes capital ship experience in the Gameplay file and your mod changes the speed of culture in the Gameplay file, then you can't simply put both Gameplay files in a mod and get it to work...you'd have to actually go through the two files, identify the changes made by each, and create a new Gameplay file with all the changes you want...there are other files such as the GalaxyScenarioDef, the String file, and the Entity Manifest (all the manifests, actually) that cannot be easily merged, and in some cases two different mods that seem to affect completely different aspects of the game in fact will have conflicting changes so merging two mods may require a lot of judgement on your part...
It may sound like a lot of work (and in some cases it is) but it sure is gratifying when you get something put together and get to actually play it...
Someone more knowledgeable than I can put up some links to effects and sound mods as I am not real familiar with any of those...I will say though that virtually every SciFi universe out there has its own conversion mod (just look at the first 2 or 3 pages of the modding section of the forums)....
