I must be a little out of the loop though with Marvel, since I've never heard of A-Bomb (but I do know all the others). Can anyone tell me who he is?
I hadn't heard of him either, but Wikipedia says
A-Bomb is Rick Jones, who was transformed into an Abomination-like creature in 2008 by the Leader and MODOK. I guess it's the trend now to turn all long-standing Hulk cast members into Hulk-like creatures themselves, since Gen. Ross is now Red Hulk and Betty is Red She-Hulk.