Kavio

Allows you to store XP and repair your items more easily. (Multi brightness level interface)

Allows you to pick up chests and barrels!

Adds an economy system for easier trading between players.

Put anything onto your head!

Lets you easily send your coordinates in chat for others to come along! (+features)

Adds a craftable item that gives you nofall!

Makes it easier to put knots on your fences by using commands!

Uses the "Silence Occasionally Broken by..." concept but with Minecraft sounds!

Plays a sound to all players when someone dies! (17-23 sounds + their variants)