I have always thought the Korg Prophecy was something special in this regard. It can get so aggressive, rude even, yet remain (to my ear) so very musical.
The on-board analog distortion of the Studio Electronics ATC-X(i) can give it a timbre no other monosynth can touch as it concerns dirt.
That said, one thing I consider as it regards "aggressive" synths is that, to me, the ability to overdrive, be punchy, provide ear-poke, and so on, is not the deciding factor, even if those aspects contribute a lot to the determination. After all, you can take any synth and run it through a dirt pedal - and you'll get dirt, but it may not sound aggressively dirty. To me, preserving a sense of articulation and expression is essential, and the synth comes to life when it is combined with timbral aspects that suggest the synth is "going off the rails," or approaching the limits of what would be considered musical in the context of the arrangement. Non-linear response tends to work well for this, especially when it occurs on multiple axes of control.
The SCI Pro-One can be pushed in this way to give up the goods. I think this is a primary reason why it was so adopted by those creating music that was described as Industrial, EBM, and so on.
Well-programmed, I think many of Yamaha's FM synths qualify. Their degree of potential articulation combined with the ease of non-linear, non-harmonic response makes it easy to ride these machines on the edge. Their quick envelopes and inharmonic timbral control can yield edgy, cutting sounds.
I think the Waldorf Pulse can produce aggressive sounds when being used for hard, fat basses and percussives, and sometimes leads as well. Its relative lack of vintage flavor makes it excel in this way.
Last in my post, but certainly not least, is the Clavia Nord Modular. Take the basic sonic fingerprint of the Nord Lead 2, expand it greatly, and allow for the control to create musical timbres that are all kinds of raw and aggressive. From FM to waveshaping, filter feedback to modulated ring-mod, this synth does a lot and does it well.
p.s. - two synths are regularly touted as being good for aggressive sounds - the Access Virus and the DSI Evolver. I found neither of them to be so, but many others do, so this shows just how subjective it all is, and that in the end, as with all things, you have to use your own ears, taste, and frame of reference to make a decision.