Look freaks, you don't need pages and pages of dozens of different kinds of poison for your RPGs. Most purposes you need can be fully covered by a poison that kills quickly and violently, a lethal poison that is tasteless and odorless, a poison that is chloroform, a poison that causes gradual deterioration over weeks, and a nonlethal poison that makes you weak. That's it! You should still give it some panache, come up with a cool name for the poison and so on. But the mechanics should be simple.
Determine the "cost factor" for your setting. Poison costs will scale with that factor. The "availability" shows the chance you can find a meaningful supply in the right circumstances.
- Quick weakening poison. Obvious smell and color. Cost factor x1 Availability: 4-in-6.
- Quick knockout poison. Obvious smell and color. Cost factor: x2 Availability: 2-in-6.
- Quick lethal poison. Obvious smell and color. Cost factor: x3 Availability: 3-in-6.
- Slow lethal poison. No smell, dissolves totally. Cost factor x10 Availability: 5-in-6.
- Quick lethal poison. No smell, dissolves totally. Cost factor x100 Availability: 1-in-6.
The DM should determine the name, color, application (bloodstream, inhaled, consumed), what the right circumstances for finding a meaningful supply is, and any partial effect on a passed save, based mainly on vibe.
You can use this generator for symptoms: https://perchance.org/rpgsymptoms
Or this one. It's pretty good: https://blog.d4caltrops.com/2022/05/d100-deadly-diseases-alarming-ailments.html