Veggies are always a good thing to munch on ... anything that's low sugar is something you can eat in quantity. Things like celery, broccoli, cauliflower, cucmber, etc. Carrots are higher in sugar and contain significantly more
calories.
You can also airpop some popcorn for a healthy and filling low-cal snack. 6 cups of airpopped popcorn (about 1/4 cup unpopped) is about 130
calories and that much popcorn can last a pretty long time if you're munching through a movie or something.
But if you want the truth - the best thing to do is to break the habit of eating mindlessly while you're watching TV or working on the computer. You can choose to not eat while you're doing other things ... it's not easy at first, but it can be done.