FREE ONLY PLEASE
I'll start.
the first one I reach for is not the greatest on the planet, but very handy, low CPU, no learning curve: Luxonix LFX-1310
http://www.kvraudio.com/product/lfx_1310_by_luxonix

Next, I think the EFFEECTIZER qualifies:
http://www.kvraudio.com/product/effectizer_by_gsi

GLITCH has multiple types of effects in it too
http://www.kvraudio.com/product/glitch_by_illformed

What else is out there?

