I've added it (though as it's unavailable, it doesn't show up by default). I've also added the Lalboard (http://lalboard.com/), which is an open-source project to recreate it.
Particularly annoying when there's such a wide range of non-split keyboards with nice keyswitches. You've got all the bizarre layouts you can eat, but you still get the option of a more standard one too.
I wish people would just copy the MS Natural Ergonomic 4000, but with better keyswitches.
Having said that, I did make myself a split ergonomic keyboard with a full set of keys (107, if I recall correctly). Here's a picture:
https://photos.app.goo.gl/XPvTVdwaP2tog8zj6
I ended up not liking the arrows where they were (was used to the Ergodox layout where they are not an inverted T but wrap the big right thumb keys) and stopped using it. Having the number pad was great for Blender, but hard to reach.
With cheap keyswitches, cheap microcontrollers, and cheap 3D printers around... there is no reason not to build a keyboard that meets your exact requirements. I use an Ergodox EZ, though, but may experiment more in the future.
This is why I made the gallery -- it's an easy way to compare a lot of options, even if not all options have filters.
I have just added the C989 Ergo, which was mentioned elsewhere in the discussion. That seems to be the closest mass-produced, mechanical keyboard to the MS Natural: https://c9ergo.com/
I replaced my MS keyboard with a Kinesis Gaming Edge - it's a pretty good replacement, and I've found being able to separate the two halves of the keyboard and put them about shoulder width apart makes for a very nice typing experience. No numpad, and I'm not a huge fan of the home/end/pgup/pgdown placement, but you can add a numpad in a second later if you want to.
I like having all my often used keys in the home row. I don’t have to move my hands to use arrow keys because I use vim bindings on a layer. Hyphen,underscore, grave and tilde are on the home row, too. I can program a key to be a combination of key presses, too. My workflow is much improved using my own custom keymap and keyboard.
The main focus of most of these keyboards is ergonomics. Even if it comes at the cost of learnability.
This is also why there's a lot of variation. People are dropping and moving keys to deal with things like hand size and existing RSI.
>I wish people would just copy the MS Natural Ergonomic 4000, but with better keyswitches.
You can probably get someone to 3d print and solder you a one-off keyboard that fits the bill. It's doubtful anyone other than MS will mass produce such a thing though.
I am a very satisfied user.
I have used ergonomic keyboards for long time. Some have been passable, such as one or two models of Adesso and Microsoft keyboard. Nothing has offered the combination of qualities that the Goldtouch offers. Comfort, robustness, adjustability, cost.
I have added a link at the very end to one such site, http://xahlee.info/kbd/ergonomic_keyboards_index.html , where the Goldtouch is listed and reviewed.
I've fixed the filter. I'd tried to do it entirely with CSS classes, but I think that was unrealistic.
(I also removed ErgoDox EZ, leaving only ErgoDox. It's the same design, and other keyboards where there are one or more manufacturers making the device to whatever quality aren't split out like this.)
[1]https://needgap.com/problems/96-one-hand-keyboard-keyboard-a...
Anandtech reviewed it seven years ago:
https://www.anandtech.com/show/6682/first-impressions-the-te...
(Maybe you did a case-sensitive search, or set some filters? I have it as "ErgoDox EZ".)
Hopefully it's helpful for a quick overview of the options that exist. Many of these keyboards are DIY (available as a kit, or sometimes just a PCB and case plan), but some are available assembled.
https://aposymbiont.github.io/split-keyboards/
(There's also https://jhelvy.shinyapps.io/splitkbcompare/ for direct comparison of ergonomic (with thumb keys) keyboards.)