What type of food do pet gecko eat?

Depending on the gecko species will determine it's diet:

The Leopard Gecko

This animal is an insectivore.

In the wild this animal would feed on a variety of live feeders such as: insects, arachnids, arthropods, smaller reptiles, small mammals.

In captivity reptile hobbyists have many live feeders that are appropriate for a leopard gecko such as: brown crickets, field crickets, locust, silk worms, tomato worms, meal worms, dubai roaches.

The Crested Gecko

This animal is an omnivore.

In the wild this animal would feed on a variety of live feeders as well as saps, pollen, fruits and nectar.

In captivity reptile hobbyists have created a formula known as crested gecko diet. This is a meal replacement powder (MRP) that replicates everything essential in the animals natural diet. It consist of all the magnesium, calcium, phosphorous and vitamins the animals need to thrive in captivity. They are also allowed live feeders throughout the days as well to promote exercise and stimulate activity. These animals cannot be fed baby food.