I agree that MYT stickers would be excellent. I'm sure they'd sell a pile of them at each gig.
They may not have any stickers available today, but they definitely did at some point. I got either a "Blur Are Shite", or "Mogwai: Come On Die Young" sticker way back at a gig around 2002-2003 I'd say. Was affixed to a long since discarded dresser drawer. Haven't thought about that in a while. Wish I could recall exactly what the sticker said. All I know is it was wide and narrow, black with white text.