Wenda
A tool for VIP players to manage their inventory (though it works for anyone). It shows how long until subscriber benefits expire (for all alts), how many empty inventory slots there are, and which carry-alls are in your inventory.
GoneFishing
Makes it easier to switch back and forth between your weapon and your fishing rod, and provides a handy button to cast your line without taking up a quickslot.
ToolTime
Shows all of the crafting tools in your inventory and equipped slots, so you can swap between them.
ResourceManager
Track which alts have which professions, and what resources they need.
BulletinBoard
A purely chat-based plugin that lets you send reminder messages to your alts.
Packrat
A tool to keep track of the carryalls your alts have in inventory, vault, and shared storage. You can give them names, and the plugin keeps track when a carryall moves from one place to another. (At least that's the hope!)
Quippy
Helps you keep track of your alts' equipped items.
Travel
Type "/tg " and part of the name of a travel skill location, and it opens a window with those travel skills that you can click on. Currently only working for Hunters.