Add N to (X),
Air - on their '98 album "Moon Safari",
"Alien of Ufomammut",
Aphex Twin - has three of them,
Apollo 440,
Beastie Boys,
Apotygma Brzerk,
Richard Barbieri - guesting on No Man's "Flowermouth CD,
Biosphere,
Blancmange,
Beborn Beton,
Bunnydrums,
Cake,
Camoflauge,
Cartwheel,
Chris Carter,
Vince Clark,
Coldcut,
Die Krupps,
Electronic Dream Planet,
Front 242,
Front Line Assembly,
Laurent Garnier,
Dave Hewson,
Influential Melbourne,
Junkie XL,
Brian Kehew and Roger Manning of The Moog Cookbook,
The Legendary Pink Dots,
Rudiger Lorenz,
Lusk,
Zia McCabe of the Dandy Warhols,
John McEntire of Tortoise,
Mr Oizo - uses it plenty on his album FAT,
Neuronium,
Nort,
Mats Oberg,
OMD on "Electricity",
William Orbit,
Jeff Parker of Isoptope 217,
Martyn Phillips,
Ian Pooley,
Random Kings,
Remote Control,
H-J Roedelius,
Sea,
Severed Heads,
The Shamen,
Starfish Pool,
Stereolab,
Switzerland,
Phil Thorton,
Adrian Utley of Portishead - used it for guitar treatment,
YMO,
Youth
[Let us know if you have any further additions to this list.]