Most essentials features on a Skyblock plugin what you're looking for?
Create your island (/is create),
Manage your island (/is panel),
Invite your friends (/is invite add {player}),
Teleport to others island! (/is visit {player})
• Custom cobblestone ore generator! (Coal, Iron, Diamond, Emerald)
• Scoreboard and PAPI support!

Dependencies:
FastAsyncWorldEdit needed!

And more...
Tested on Paper 1.21.