The biggest surprise for me was many of the flavored potato chips. Many brands of Salt and Vinegar chips contain milk.
Another big one was Pedialyte. I have no idea what ingredient it is, but at the bottom it says “Contains: Milk”. I’m not vegan, but I don’t consume dairy. I used to use it for hydration during running events and started noticing my stomach would get upset after drinking it. Looked on the back and found that under the ingredients.
A lot of gummy candies, and some jams and jellies use animal collagen as a gelling agent.
Spicy Sweet Chili Doritos. They didn’t mean to make them Vegan, it just worked out that way.
(Not vegan, but my family is.)
Many meat substitutes like veggie burgers, hot dogs and fake bacon contain egg as a binder to hold everything together, so they’re vegetarian but not vegan. Restaurants often don’t know the difference between vegan and vegetarian, so they’ll substitute in a vegetarian product while marking it as as “vegan” on the menu. But a lot of vegans already avoid restaurant food because chances are that the vegan food is cooked on the same grill/fryer that was cooking meat 30 seconds earlier.
Milk powder and gelatin are also sneaky non-vegan ingredients. Flavored chips often have milk powder, dairy-free ice cream can contain gelatin, and chewing gun can contain casein (derived from milk). Powdered drink mixes can also contain milk proteins.
Some types of figs are pollinated by wasps that die and get absorbed by the fruit, so they’re not technically vegan. But a lot of vegans are fine with figs because it’s part of the wasp’s natural life cycle and the animals aren’t being exploited.
Many beers and wines are clarified using egg, gelatin or the swim bladders of fish… but I don’t actually know any vegans who worry about this because it’s so difficult to determine which products are vegan and which aren’t, and manufacturers might change their clarifying agent without warning.
White sugar is usually processed with bone char to remove the natural brown color, and pretty much all processed foods contain sugar.
Not food, but a lot of medications and vitamins contain whey, lactose or gelatin. Some beauty products like shampoo and nail polish contain milk proteins.
I never knew Oreos were vegan.