I agree, that would be fun. I suspect the reason there is no Antihero combo is that Antiheroes are loners.

Suppose that Antiheroes, or characters like Beggar with no Type, could get an Anticombo, like this idea:

ZEALOT
COST: 6 GOLD
TYPE: ANTIHERO
ANTICOMBO: 7 BLOOD, MINUS 1 PER TYPE IN PLAY

So if you have a Zealot (Antihero), two Pikemen (Soldier), and a Monk (Holy Warrior), that's four Types in play. Soldier, Worker, Holy, and Warrior. 7 - 4 = 3, so Zealot gives 3 Blood.

Unfortunately, playing with Zealot would probably be kind of monotonous.