Are you here and work for new version of mod? Because I have some more suggestions.
Giraffe liver and bone marrow (for DF you can use bones or nervous tissue) can be brewed into drink with effects like ayahuasca.
Cobra venom can be mixed with smoking hemp for stronger effect.
Some DF spiders and worms can be used for drugs, like IRL Myelobia smerintha, Floria species, Phoneutria nigriventer and spanish fly. Spanish fly also useful for contact poison. Also exist drug fish species.
As curses you can add diseases. Like plague. But not try to focus on curses, this is not for DF.
As diseases you also can add nipah virus (from bats), other zoonotic diseases, parasitic worms (not as vermins, only as syndromes). And even, but this may be not in setting, special diseases from Plague Inc - necroa (new, contagious type of zombies), neurax worm (are disease and spread like disease, but also exist vermins who bite your creatures and start this syndrome), Nox Eternis (disease that can rare produce vampires) and disease inspired by simian flue (can transform animals into animal people, for normal sentients is just disease).
For diseases spreading you can make some materials and syndromes that give material emission. Ways of spreading possible to give different forms of disease (lung form, stomac form, skin form, blood form etc).