There are many types of damage; Smashing, Lethal, Fire, Cold, Energy, Negative, Psionic and Toxic, but only one doesn't exclusively have its own damage set: Toxic.
Currently, Toxic damage is more of a secondary damage type than a primary. I would like to suggest a new power set focused on Toxic damage with maybe Smashing or Fire as secondary.
I haven't put a ton of thought into this, but I believe an offensive Toxic power set would either reduce defense or resistance. This set would also have a couple holds. Many of the powers would also be a DoT with them being purely a Toxic DoT or Toxic/Fire.
There's many creative ways to wield Toxic since its biological or chemical in nature.
What do you think?