This is a really broad question which is probably why people haven't responded. Check out aquabid and look at different types this can help you get an idea of what is out there.
But in the most general terms
Flowerhorns divide into three major types
The top of the chart shows the origin fish- midas x red devil (midevil) lyonsi trimac synspilum and blood parrot.
The flowerhorns on the left are the flowerhorns with pearl on the head. They divide into zz's, red dragons, and zz malaus. They way you can tell a zz is that it is mostly trimac and lyonsi, so at least it has the three spots of a trimac, the flower on the head one in the middle and the ocellus on the tail. Most also have flower lines like the lyonsi. The red dragons have a red head and a large kok so they have more midevil and redhead (synspilum), though they are not faders.
The flowerhorns in the middle have more vieja, and this is the kamfa and kamfamalau group. basically a kamfa is a flowerhorn based mainly on vieja and paratheraps species. "classic" kamfas are flowerhorns with the vieja body kok and red head, and they are based on vieja. Though more often than not these days kamfas will have blood from more than one species of vieja. The most popular and valuable kinds of kamfa in thailand appear to have many pearls and pearl crossing the head. In vietnam kamfas tend to be larger in stature and have more smaller pearling. A classic kamfa will always have a red head.
On the right we have faders. these are flowerhorns that have inherited the "fade" gene of the parrots red monkeys and midas cichlids, but given the nature of the gene (a fish at maturity will turn often all one color a variation of white red orange or yellow) there is only one very established breed of fader, the jin kang. true jin kangs will be half red (on the head like red dragons) and half yellow or orange. Many jin kangs look like red dragons until they fade.
Given the fact that when a fish fades the gene can totally block out or mostly overshadow the patterns already on the body, there are only a few kinds of faders that are really nice or worth a significant amount of money. There are some really nice faders out there, but you can cross two nice faders and still get fish that look like red devils so they are not as common.
hope this helps people please comment or correct me if i am wrong on any points. I personally am not too clear on the qualifications of the malau strain