You can sort of work backward on this. Check reviews for the fan controller in question on sites like Newegg. The reviewers will often list the make/model of the fans they are using. Then either buy those fans or check which plugs (i.e. Molex or 2/3-pin) they use and buy fans with similar connectors.

Yeah but the thing is I dont wanna just look and buy those fans, I want to know exactly why they used them with that fan controller.

All I want to know is what fans need to work with fan controllers there are only to plugs that can be used.

I had a long post typed but it's not needed. I don't understand why you won't read reviews and go from there. Many people will give some reasoning why they chose the fans they did, and most popular fans come with multiple connectors on them. If they didn't give reasoning, read reviews on the fans themselves.

Recommendations:

Scythe
Noctua
Antec
Cooler Master

Dude, I dont want to post on a forum asking for advice and the advice I get is to go to other places and suss out reviews. YES I will do that and I have in the past. Im here because I want to clear things up.

I know some fans can work with controllers others cant, My question is why is this.

I dont care about what fans are good, I just want to know how they are compatible. Like saying the LGA775 socket fits the LGA775 CPU's, because they fit.

Like you speak of multiple connectors, what are those connections and what are they for. Im going specific

Most fans will have 3 pins and sometimes 4 if they support PWM.

First two are ground (black) and +12V (yellow).
Third pin is a sensor (green) so software can read it and calculate the RPM.
Fourth pin (blue) is PWM, by which said software can control the RPM.
http://pavouk.org/hw/fan/en_fan4wire.html

Note that PWM is a motherboard-thing through which it can adjust the speed, and the motherboard also allows it to be controlled by software like speedfan.

Just check out what kind of connectors your favorite fancontroller has and look for those type of fans. If I recall correctly they all use 3-pin since they don't use PWM but just adjust the voltage on the yellow pin.

Also, the fans that do have 4 pins usually come with a 3-pin adapterplug included in case you aren't going to use the PWM, so taken that into consideration it really doesn't matter what kind of fans you buy.

Too bad there are no adapterplugs to use 775 on a 1366.

Awesome thanks! :D