I think all green vegetables offer some health benefits and nutrition, although some definitely have more nutritional benefits than others. The only green vegetable I can think of that is nutritionally deficient is iceberg letter, which does not contain many nutrients. Generally, the darker green a vegetable is, the more healthy it is for you.
Broccoli is a good source of Vitamins A & C, fibre, lutein, beta carotene, folic acid and calcium.
Romaine lettuce is a source of fiber, Vitamins A, B1,B2 and C and folic acid.
Spinach is a good source of iron, Vitamins A, C and K, fiber, lutein, calcium, folic acid.
Kale provides iron, calcium, Vitamin K and folic acid.
Brussel sprouts are good for Vitamins A and C, calcium, fiber, folic acid and potassium.
Green peas provide folic acid, Vitamins A, C and K and B complex vitamins.
Green beans contain fiber, protein, folic acid iron, phosphorus, magnesium and potassium.
Celery provides fiber, and some vitamins A, C, B6 and K.