Most people use the futures C5 fins. These are good, inexpensive canard fins.
You can get them here
An improve canard fin designed for wakesurfing can be purchased here
Many manufactures supply F4 fins, as these are a very general fin design, good for a lot of situations, and because we marketed them as the 'best' wakesurf fin out there and many followed suit.
An improved wake surf fin can be purchased here