Let's see what we have for him so far...
Tigrex
Brute Tigrex
Molten Tigrex
Grimclaw Tigrex
Zenith Tigrex
Diorex
Actually, I think we've got enough Tigrex, don't want another event similar to the Too Many Zinogres situation.
It's a Frontier Variant that has Magnetic and Electric abilites.
Here's the wiki page: http://monsterhunter.wikia.com/wiki/Diorekkusu
sweet!
A Fire-Based Tigrex would be cool, though I think the Molten Tigrex may be the closest one we have to that.
I also think that Regular Tigrex and Brute Tigrex can cause Fireblight when they throw rocks at you in a volcanic area as well.
Since Regular Tigrex doesn't appear in Volcanic Areas only Brute can do that...
Oh, well, only if B.Tiggy is in the lava, of course.