Samael Hopkins is definitely worth a look. I don't personally like the mini for him but between flaming bullets and rapid fire, he can dish out far too much damage to ignore. He's a bit of a glass cannon so if you take him, he makes a good target for the frame for murder scheme.
Also the executioner is worth a look, the mini is really nice and he can be really useful in game too. I've found he's good against a lot of weaker opponents because he heals all wounds if he kills something. Against stronger opponents his low defense can be bad if you can't finish them in melee in one go.
Other than that, the Ortega box is a good next step as they can all pretty much just go straight into any guild crew and add a lot of punch.