You Could Add a Biohazard Class
Could be done easily enough with

Could be done easily enough with

Infinite possibilities.
Also there are a ton more that can be added to that.
Sounds really cool! Perhaps their buff could be a percent chance to apply passive poison damage?
Wheres my homie Nocturne. I feel like he should be a 1 or 2 cost champion with a passive rather than an ability. -Umbra Blades: Every 5th/4th/3rd attack cleaves for bonus damage and heals nocturne.
Poison passive.
I like the idea behind having Biohazard, since it allows Champions from Zaun or Poison based champions to be added into TFT.
My question for you is what would the Biohazard Trait bring to TFT? Perhaps it give Biohazard Units the ability to inflict a Magic DoT after using a spell?