There are many flowerhorn types nowadays because there are many breeders of hybrids of the original flowerhorn varieties. The ability to produce new strains of flowerhorns is actually part of the challenge of raising these fish. So even as we speak some breeder may be mating flowerhorns and producing new strains that have never been seen before.
One of the more well-known varieties of flowerhorn is the Golden Monkey. At the start, Golden Monkeys usually had white eyes while their bodies had green, grey and metallic marks. Over time, some offspring of this breed were observed to develop red eyes as well. You may observe that the Golden Monkeys have broad stocky bodies whereas other flowerhorns may not. A Golden Monkey differs from the similar Golden Flowerhorn because it has more pearl markings on its forehead hump.
The Golden Flowerhorn might also be known as the Kamfa breed. This fish variety might have white, red or yellow eyes and a body that displays both flower and pearl markings. (Note that not all Golden Flowerhorns have the flower line markings.) Ideally, the Golden Flowerhorn should have a thick body and a face that is full and rounded with sizeable gill covers. A distinctive aspect of the Golden Flowerhorn is that it has a fan-shaped caudal fin.
You may have heard of the Zhen Zhu variety as well, a fish with mostly red and golden toned markings on its body. The body of the fish itself is shaped like an egg, with long strands of fins. Adult Zhen Zhus may possess a caudal fin or tail fin that tends to droop. One way to distinguish the Zhen Zhu from other flowerhorns is its bulging eyes, which tend to be red in color among many such fish. Another way to determine if you have a Zhen Zhu is if its lips tend to bulge out, especially the lower lip. Zhen Zhus are prized for their color markings as well as pearl and flower markings.
One reason you could be having difficulty determining flowerhorn types is that your fish could be a brand new hybrid, the result of cross breeding of existing flowerhorns. Some varieties are so new they have yet to be named. If you are having a hard time telling which variety of flowerhorn your fish belongs to, you can take the easy way out and ask the breeder what flowerhorn types the parents were - this can help you check if your fish is a new hybrid altogether.