There are that mining facility, Telos, Dantooine. Makes 3 Worlds.
Checking Screenshots, movies and concept art.
There seems to be a jungle/swamp world and a city world as well.
And one of the interviews talked about the sithlords trying to perform some kind of ritual on a world with sith tombs to gain more power... ( any one know such worlds, I'm not an expert on SW lore at all )
That would be around 6 worlds if some of those don't mix together.
Sevent planet would prolly be a snow/ice world of some sort. At least I hope so :3 ( Better then Hoth I hope)