I will admit that Legendary Pink Dots/Tear Garden were a bit underground (and much more synth based), since they didn't really fall into any one category, but they had a healthy following. Golden Palominos was a Bill Laswell produced project.
But here's one more from Stabbing Westward. I tended to like this whole umbrella category that I called hard pop -- Garbage, godhead, Stabbing Westward, God Lives Underwater, Gravity Kills, Gary Numan (although he didn't really sound like any of the others, his blending of synthesizers and guitars in the 90s elevates him to minor deity status in my heart), KMFDM, Nine Inch Nails...