[Shardphoenix]

Mightypeon, topic specifically states CBM.
So, in CBM we have (non-national):
Death - Bane, Bane Lord, Wraith Lord and all the Tartarians you want.
Death+Blood - Vampire Lords. Tough, undead and immortal. What`s not to like?
Death+Water - Hidden in Snow, Wendigo
Water: Sea King, Water Queens, Ancient Krakens. Krakens also come with random paths, so diversity!
Water+Earth - Grendelkin. Very tough, buth with no magic paths and somewhat inferior mobility
Earth - Granite Cyclops and Earth Kings. And mechanical giants can be devastating against some opponents.
Earth+blood - corrupted Earth King. Only one, a good one.
Blood - Heliophagi, Demon Lords.
Blood+fire - archdevlis
Blood+water - ice devils (they are like poor man`s archdevils)
Blood+nature - I don`t know... GoR-ed ettins from Improved crossbreeding, maybe?
Blood+Air - nothing, but you can GoR a storm demon. Those are potent thugs.
Air - Shishis (great raiders), Great Eagles (more of counter-raiders), Asynjas(stealthy titan-sized SC chassis who can cloud trapeze). Also Air Queens, if you need them.
Nature - Sleepers, Tarrasques (strong out of box, but bad mobility), Treants (VERY strong in forests, esp. in rooted form, weaker outside).
Nature+Earth - Wild Ettins good resistances and can use twh-handed weapon+shield, but only one misc. slot).
Fire - Zmey-Zmey-Zmey. Also Emberlords. Oh, and Fire Kings.
Fire+Death - King of Banefires.
Astral - err.. Wat? Well, it has Wish. And ton of anti-thug spells.