Healthy snacks can include grapes, apples, nuts , seeds, yogurt, cheese, pretzels, air popped corn, etc. Just make sure that you watch portion sizes.
Also, when you want to snack, try to do something else, like take a walk, listen to music - anything that might take your mind off food for a few minutes.
I like avacado. Tends to help me if I put it into a salad-helps me stay full longer. Happy dieting