The Interplanar Union of Kobolds (IUK, pronounced "yuk") is my favorite long-running gag I work into every campaign. Their HQ is in Sigil, but they have locals on most major planes. No longer will the long-suffering kobold serve its draconic masters! A fair day's boobytrapping for a fair day's loot!

Recently, on certain planes, they've opened membership to non-kobolds in unionized dungeons in a mirror of the real-world IWW's philosophy of industrial (rather than trade) unionism. There's been some debate about forming a new union that's more inclusively-named, but it hasn't gotten very far.

In-game, unionized dungeons tend to be much more organized, drawing inspiration from the old story about Tucker's Kobolds. The kobolds are armed and armored and show strong teamwork and planning, making for a real tactical challenge for adventurers who think they can just mow through. They are, however, very open to diplomacy, and have been known to work with adventurers on occasion, especially against bourgeois dragons who attempt to enslave them.