If on one end of the guitar pedal spectrum there are Tube Screamer clones, then on the other end is organ simulators. That is to say, there aren’t that many of them. Earthquaker has one called the Organizer that I’ve always liked the sound of, and I’m sure there are others in this category that I’m not aware of, but most of the time folk seem to utilize a complicated balance of pitch and swell effects to get the desired organ tone.
Electro-Harmonix knows a thing or two about just that, since the company’s POG2 pedal can be configured for just such a tone. But if you’re looking for a simpler, smaller solution for that specific organ sound, because who knows if the next hot sound in metal will feature an organ so you may as well be prepared, then Electro-Harmonix’s new B9 Organ Machine will fulfill all of your needs.
It has 9 presets ranging from jazz to cathedrals, crammed into a standard EHX chassis. The tones in the demo video sound pretty great, especially when combined with liberal amounts of reverb.