You mean like, DDT, Thomas? I believe Toluol was developed as a nerve agent but tended to make a better fuel air explosive. However it's such a good solvent we use it in almost everything needing a volatile.

Used drums are scary unless you know what's been in them. I got mine from the heavy duty shop where they were used for motor oil and 15 gal. grease barrels for various tranny and differential fluids. 

Frosty The Lucky.

The modern pesticides; DDT is actually fairly "nice" the big problem with DDT was the effects on birds and that is was so persistent.

The Organophosphates: "These chemicals are the main components of herbicides, pesticides, and insecticides."

                                          "The Novichok, or “newcomer” class of nerve agents are lesser characterized, weaponized organophosphate agents"