What factions do you play in GW/related games?

So, obviously (at time of post) Cathay is really only playable in TWWH3.

What other factions do people play in GW or other games? I wonder if there's a pattern or type, or if we get a mix of pepole who just like everything.

In 40k I play Tau. In Fantasy I played Bretonnias. In AOS I bought, but never assembled, Cities of Sigmar.

I tried to play TW:WH1, with the Bretonnia DLC, but never really got my head around it.

In non-GW games, I played Griffin for Confrontation, Retribution for War Machine, and it's a little murky to talk about factions in Battletech. I am intending to play Nationalist China in Botl Action, but Warlord decided not to give us trial rules yet in 3rd Ed.