There are mainly four types of blades in knives.Serrated Edge A serrated edge has very sharp grooves and ridges all along the blade which help to cut harder foods. They can also slice softer foods without crushing them and putting them out of shape. Bread knives, tomato knives, etc have serrated edges. Straight EdgeThis is the most common type of edge. It is also known as a flat ground edge. It’s found on most knives including chefs’ knife, paring knife, etc. Hollow Ground EdgeThis type of edge is seen in most Japanese knives. Here the blade tapers down from the center of the blade to a very sharp cutting edge. These knives are extremely sharp but are prone to breaking and wear and tear. They need to be sharpened frequently.Scalloped EdgeThese types of blades have dimples along the length of the blade which prevents wet or sticky food items from sticking to the blade. This is especially useful when cutting foods like raw fish or sticky vegetables like lady's fingers.