Feel free to be loose with your definitions. "Not usually considered a drug" is fine to qualify as "non-drug", for instance. I'm not really thinking so much of "foods", though, but maybe "food ingredients" and substances found in food ingredients are fine, especially if they're quasi-drug-like or if you'd get a lot of the same benefits/enjoyment from it consuming it straight rather than in food.

Also ITT, tell other users why their substances actually are drugs actually.

Mine:

• Chamomile - good for my mood and gives me vivid dreams.
• Capsaicin - I and Wilbur Scoville are well acquainted.
• Cacao - I don't really do cacao any more because I've quit caffeine, but I include it here because I still miss sucking on unsweetend baker's chocolate daily.