There are many types of Hamon with various shapes but the main shapes are the straight Hamon lines or the wavy Hamon lines.
Here are some patterns that exist
Suguha
This Hamon is in a straight line parallel to the edge of the sword. This type of Hamon is very old and is present on the most ancient Katanas, it has remained the most classical shape. There are variations of this Hamon because it has been much appreciated and used by many smiths like the hiro-suguha or chu-suguha or hoso-suguha.
Notare
Slightly wavy Hamon
Gunome
The Gunome represents a series of semi-circles referring to the stones used in the traditional game of GO, seen from the side. The name of this hamon is therefore directly inspired by the game of GO. Then, with the Kamakura period various hamon based on Gunome were produced like gunome choji, gunome kataochi or gunome kaku.
Midare
Notare
This Hamon looks like a light wave of water. This hamon started to appear at the end of Kamakura period, the founder of this hamon is the famous Masamune. This hamon became one of the most popular and influenced many blacksmiths, especially in Okinawa.
Ko-Midare
Ko-Midare Hamon is a hamon with small irregular and very complicated patterns. This Hamon line was often represented on swords forged at the end of the Heian period, it is meant to stand out from the traditional Hamon with few shapes.