A little context: The USDA recommends that women between the ages of 19 and 30 on a 2,000 calorie-per-day diet eat 46 grams of protein a day, and for men of the same age, 56 grams protein per day. A table of exactly how much protein you need for your age and body can be found here.
Keep in mind that not all proteins are created equal. It will take a larger amount of leafy greens than, say, beans to make you feel full. But if you're looking for a few extra grams here or there along with the vitamins and nutrients that veggies provide, consider getting even more involved with the ones on this list!
1. Chickpeas
2. Kale
3. Quinoa
4. Broccoli
5. Chia Seeds
6. Hemp Seeds
7. Spinach
8. Rice
9. Avocado
10. Lentils
11. Tempeh
12. Split Peas
13. Sesame Seeds
14. Cauliflower
15. Alternative Nondairy Milks
16. Edamame
17. Black-Eyed Peas
18. Arugula
19. Cashews
20. Pepitas
21. Seitan
22. String Beans
23. Almonds
24. Asparagus
25. Sunflower Seeds
26. Cucumbers
27. Tofu
28. Beans
All information sourced from the USDA. Now you'll never have to ask a vegetarian where they get their protein from again!
UPDATE
Some entries have been updated with the most recent protein counts made available by the USDA.