There are several main types of surveillance cameras available in the market. Bullet cameras are small and cylindrical and are primarily used for outdoor surveillance. Dome cameras are compact and can rotate 360 degrees, making them a popular choice for indoor surveillance. PTZ (pan-tilt-zoom) cameras are equipped with motorized controls that allow them to move and zoom in on objects remotely. Wireless cameras are connected to the internet and can be accessed from anywhere, making them an excellent choice for remote surveillance. Hidden cameras, also known as spy cameras, are small and discreet and can be used for covert surveillance. Lastly, there are thermal cameras that use heat to detect movement and are commonly used in areas with low lighting conditions.