https://www.maltron.com/store/p20/Maltron_L90_dual_hand_full...
It looks ugly, but they were the original inventor of contoured keyboards I think.
Part of my dislike might come from the MX Black switches they used at the time, and I gather that alternatives are available now. Another factor is their keycap profile and the placement of the switches, which mean that if your fingers get misaligned, you hit a gap between the keys. This is more irritating than it sounds.
While not a criticism at the time it was built, it's also worth noting that there was (and is, I think) no layout customisation other than a choice between fixed layouts with a couple of switches on the underside of the keyboard. The case is vacuum-formed, which looks and feels cheap compared with modern competitors, and the bottom is glued on which would make repairs difficult (not that mine ceased to work).