I fear the Izzet one could be the best possible charm we get from the set because other combinations like UB, UW, GB have possibilities to push the acceptable power levels so they could end up with rather clunky designs. On the other hand I might just be talking out of my ass.

Edit: Btw Izzet is a teribble name for a fictitious fantasy world guild (I know, I am several years late for this comment) because it is a real world name. A friend of mine has a boyfriend named Izzet.