You also have a decent variety of materials to choose from. These table sets often come in:
Wood is a classic and sturdy option that makes a great base for any table and chair set, even those for children. Wood is commonly used in table and chair sets for older children. Choose wood if you want a style that is starting to look like classy miniature versions of adult table and chairs sets.
It also very common to see children's table and chair sets made out of plastic. Since plastic holds less weight, it's commonly used for smaller children. The rounded shape of the plastic also gives more of a playful feel, like the set itself is one of the toys in the room. Choose plastic sets for smaller children or if you're looking for very colorful and playful designs.
Some toddler & kids table & chair sets make use of metal, but it is not the go-to material for kids furniture, except for beds. Metal tends to be cold, but on the other hand, almost indestructible which does become an upside in a kids' space. Choose metal for a more casual, modern or even industrial space.