Protector Redo
TenPlus1

Lets players craft special blocks to protect their builds or disable PVP in areas.

Traders
Sokomine

Configurable mobs/NPC which can trade for you.

Smart Renting
AiTechEye

Smart renting: Rent out your locked things and earn money!

TP Gate
AiTechEye

Teleport through the gate

Global Bulletin Boards
FaceDeer

Allows creation of global bulletin boards where players can post public messages

Protector Redux
sorcerykid

An efficient and flexible node-based protection scheme for multiplayer worlds