In all honesty: any vegetables you can eat :)
The majority of nutrition clients come in with very low vegetable intake ratios. Since vegetables are high in vitamins and minerals, but low in overall calories, they should be a staple in your daily diet. Take note that vegetables do not provide everything you need for a balanced diet and optimum health, but the majority of us could certainly benefit from obtaining more vegetables in our diet.
If you struggle with finding vegetables you like, try preparing them in different ways. Steam, stir fry (no more than 1 tablespoon oil for 4 servings), roasted, raw, blanched, mashed, etc. All of these are great ways to take in your daily veggies. You can even try adding a handful of spinach to your morning smoothie or dipping raw veggies into hummus as an afternoon snack.
Try to think outside of the box and always opt for the cheapest vegetables when buying fresh (cheap means they are in season). Keep frozen veg on hand for quick soups and stews during colder months and try some pre-washed, ready-made salads during summer. Look into vegetarian recipes online or at your local library to get a little more inspired. You could also host a recipe swap with your friends and have everyone submit a veggie recipe.
Open your mind and your taste buds and you're sure to find something delicious!