The following books are filled with poisons and herbs descriptions. Most were written for specific editions of Dungeons and Dragons, but most of them can easily be adapted to any roleplaying game.
From Ajida to Silver Wine, whether they are real poisons or fantasy creations, coming from plants or animals, toxins or lab mixtures, here are 101 poisons for D&D 5th edition.- Thanks to AideDD
Supplement for The Guide to Herbs for RPG's
Hello Fry, it's a ... *[stops mid-sentence, throws a D20 and a D6]* pleasure to meet you. Gary Gygax voicing himself in "Anthology of Interest I" on Futurama TV show