1. Seitan. Seitan is a popular protein source for many vegetarians and vegans. ... 2. Tofu, Tempeh and Edamame. ... 3. Lentils. ... 4. Chickpeas and Most Varieties of Beans. ... 5. Nutritional Yeast. ... 6. Spelt and Teff. ... 7. Hempseed. ... 8. Green Peas.