It looks like you're new here. If you want to get involved, click one of these buttons!
Lusternia has aetherships for inter-planar travel. Pretty active community.
Miriani is a pretty decent one with an average playerbase. RP is enforced but you are not expected to be very in-depth with it, and it definitely has a heavy amount of exploration involved if you decide to fly out of local space.
The site is toastsoft.net and you can point your client to toastsoft.net:1234 to play.