I like the idea of a potentially deadly, but still not to be takes seriously villain team. These guys are all experienced criminals, but they might actually be better off going solo.
Death's Head and the Deathtones - Government Jobs
Death's Head - A new one, but with an old costume. Thinks he's the Taskmaster, but he's really more like Sabertooth. Somewhat dimwitted, he has his moments.
Zaran, the Weapons Master - If it absolutely positively has to die overnight, Zaran's your guy. Killing comes a little too easily to him, and he's not exactly the most even tempered guy around. Out of a job after he accidentally gutted Batroc with a shrimp fork. Simply cannot find a shirt in his size.
Whirlwind - Faster than Quicksilver, but can't beat Ant-Man. Recent bouts of depression have left him with a bum rap among the cape and cowl set, and he needs a steady job doing the only thing he knows. Tends to be a burden unless properly motivated.
Hobgoblin - It's Bart Hamilton! No, it's Ned Leeds! No, it's Flash Thompson! You know what, come back in 15 years and I'll tell you who it is. In any case, he' a dangerous sociopath and a bad team player.
Boomerang - Cowardly, underhanded, and more than a little ridiculous, Boomerang is nevertheless an extremely dangerous individual. Starcream with boomerangs. Including the voice.
Lady Octopus - Unpopular among the villain set, she's got an identity crisis and a bone to pick. Probably the strongest of the bunch, and that's freaking pathetic.