I am a 20 female, i take omega-3 every day and i eat mostly healthy food , what other vitamins could i take to maintain my health ?

Vitamins: If you are othewise healthy and are eating a balanced diet, you likely don't need additional vitamins. If you want to ensure you have them covered, take a multiple vitamin tablet.

Healthy: At your age, If you are in good health, eating a healthy diet, exercising regularly, getting enough sleep & rest, then you don't need any supplemental vitamins!!