Title says it all, are there varieties that any of you are aware of? I haven't been able to find anything, closest to yellow I have seen is a Jaguar. The less aggressive the better.
Above and below is Cryptoheros (aka Archocentrus) nanoluteus, from Panama, non aggressive and stays fairly small, easily adaptable to small tanks, 40 or 50 gallons or so.
There is also xCichlasoma pearsei that is a beautiful mustard yellow, but because of their size, you should have a minimum of a 200 gallon tank.
Another Parachromis, a tad smaller than managuense, is motaguense, but more aggressive
female above, male below
.
If you want to go South American, and without a heater.
Australoheros sp red ceibal in breeding color is amazing
As fwprawn said, Archocentrus multispinosus (rainbow cichlids) are yellow when spawning. There is a brighter variety that appears more orange and the more common golden/bronze variety.
Let's not forget the awesome Gymnogeophagus balzanii.