Thin crackers are a type of snack food that come in many different varieties. The two most common types of thin crackers are saltines and wafers. Saltines are a type of cracker made with flour, water, yeast, and salt, and are usually square-shaped. Wafers are a type of cracker made with flour, sugar, and butter, and are usually round-shaped. Both types of thin crackers are typically served with soup or salad, or as a snack.