The choice is huge - there are snaffle bits made of a wide variety of materials and in different shapes. Which snaffle is best for you depends on your horse's anatomy, temperament and habits. An anatomically shaped, double-jointed water snaffle usually encourages horses to chew more, so if your horse doesn't chew enough, this snaffle may be optimal. On the other hand, if your horse already chews a lot, it might just play with this snaffle and not accept the aids. In that case, a single bridle would probably make more sense. However, this type of snaffle is not suitable if your horse likes to lean on the bit.
Most horses accept a single bit, anatomically shaped eggbutt snaffle very well. It lies very comfortably in the horse's mouth. But even this snaffle is not well suited for horses that tend to push against the hand. In this case, a double jointed version would be better.