ArkInventory
Allows viewing of your (and your alts) Bags, Keyring, Bank, Guild Bank, Inventory and Mail items.
Legion 
Mists of Pandaria 
The Burning Crusade 
Wrath of the Lich King Addon Details
Expansion
Categories
Developers
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ArkInventory is a WotLK addon for patch 3.3.5a that provides better functionality to your bags and inventory.
Features:
user-configurable window width and height
separate keybindings for each location for easy viewing
assign items to a category of your choice (overrides the default assignment)
assign categories to the bar of your choice
unlimited number of bars (there are practical limits though before your screen becomes full)
sort each bar differently if required
user-configurable bars per row
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