Better Command Blocks
ThePython10110

Adds command blocks similar to those from a certain other voxel game.

BlockHead
Silver Sandstone

Lets you put a block on your head.

Simple Waypoints
chon

A simple way to mark and teleport to important locations in your world

Inventory Admin
Impulse

Enables admins to manage the inventory of players.

Terramod-Staff
Bapt-tech

Many commands and functions for admins and moderators

Player_join
Salzar

Adds a custom join and a left message.

Ascend
kestral

Ascend by chat command, if possible.

Playerhealth
Simon

fill your hearts (HP)

Voxelforge /sit and lay commands
VoxelForge

Sit and lay using chat commands