Inventory
In games that allow players to stockpile items, gamers may use inv as shorthand for "inventory." For example, in an MMORPG, a player's inv may contain armor, weapons, potions, and other items.
Typically, players use inv when discussing items they are willing to trade or sell from their inventories. These discussions often take place in game-related forums or Discord channels, which have been created specifically to allow players to negotiate trades and sales.
Example
I've got some rare items in my inv that you might like
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An abbreviation for inviting someone to join a multiplayer group; used commonly in MMORPG games, where players group together to accomplish objectives.