/back - returns to last known location (on death, on teleport last location is saved)
/craft - opens a crafting bench
/enderchest - opens your enderchest
/sethome, /home, /delhome - saves, teleports and deletes your home location
/inventory [player] - opens the current inventory of another (online) player
/slimechunk - if the player is in a slime chunk you will receive a message saying that, otherwise it will show you the coordinates of the closest slime chunk
/setspawn, /setspawn [player]/[x y z], spawn - sets and teleports to the spawn
/setwarp [warpName], /warp [warpName], /delwarp [warpName], /warplist - saves, teleports, deletes and shows a list of warp locations.