guide to potions and ingredients
I don't think I've ever shared this here, but many years ago I created an extremely exhaustive guide to potions and ingredients in the Harry Potter canon, also based heavily on real-world knowledge and history of herbalism.
I use it as a reference all the time so I thought it might be useful! In the interest of completeness I also included stuff that's only vaguely canon (from video games etc) but since it was made so long ago it doesn't include information from the FB films, Cursed Child, Hogwarts Legacy or the mobile game lol. But it's very very exhaustive and detailed haha, much more than the wiki if I do say so myself.
It's split into first a list of potions (many of which include relevant historical information, probable ingredients, and even brewing instructions where those exist) and then a list of ingredients (also with discussion of real-world applications/significance of those ingredients.)
It's designed so you can easily invent your own potions for fic-writing purposes or make a more educated guess as to the ingredients of potions that exist in canon, rather than a hard-and-fast guide to what is or isn't canon. Basically you don't have to follow the information exactly haha, it's just a guide. If you look at the ingredients of potions that we do see in canon, they usually make complete sense with the purpose of the potion and have obviously been well researched.