There are several Skyland style servers, in this series I'm playing on The Pixel Shadow's server, as I have permission to record there, but it seems to be down more often then it's up. There are a few other public servers that host similar games that seem to be online much more regularly, like all the time. There are a series of levels and quests that you need to complete to progress onwards. This is a perfect style of playing for me as there is a very defined goal, complete all the quests and max out the levels. Once I reach that point I'll probably stop playing on the server.
These are the mods on the server: 3d_armor, 3dmushrooms, bedrock, beds, boats, bones, bucket, carts, cozy, default, doors, dye, farming, fire, flowers, pbj_pup, protector, screwdriver, sfinv, signs_lib, skyblock, stairs, stamina, tnt, torches, tps_items unified_inventory, unified_inventory_plus, vessels, walls, wool, & xpanes.