The Hulkbusters are a large military force designed to stop the Incredible Hulk.
The Hulkbusters on the Heroes Reborn world consisted of the Hulk, She-Hulk and Doc Samson, all of whom had been transformed by the gamma bomb developed by Stark Industries.
In the Ultimateverse the Hulkbusters consist of a team of S.H.I.E.L.D. agents with special training and silver and black body armor. They are first seen in the Hobgoblin story arc where they are used to fight Harry Osborn in his Hobgoblin form.