They are a plant's defense system. Lectins are potentially toxic plant proteins which can stick to your cells and cause microscopic tears in your gut lining.
Tomatoes Peppers Potatoes Eggplant Goji berries
Cucumbers Zucchini Pumpkin Squash
Chickpeas Peas Lentils Soy All Beans
Wheat and Rye Oats Corn Rice Quinoa Buckwheat
Almonds with skins (blanched are ok) Peanuts Cashews