Stone-With the rank Stone you can join the server when its full, have a nickname, do /workbench, and disguise into a pig and cow by doing /d pig or /d cow.
Iron- With the rank Iron you can do everything that Stone can plus, set multiple homes, and disguise into a bat, chicken, zombie, creeper, wolf, skeleton, and spider.
Gold-With the rank Gold you can do everything that Stone and Iron can plus, do /speed, clear inventory, do /fireball, and disguise into a horse, ocelot, squid, and mooshroom.
Diamond-With the rank Diamond you can do everything that Stone, Iron and Gold can plus, do /fly and disguise into a enderman, ghast, slime, villanger, blaze and zombie and skeleton horses.
Obsidian-With the rank Obsidian you can do everything that Stone, Iron, Gold, and diamond can plus, gamemode creative, /heal, /repair, and all block and mob disguises.