keyboard.io has it on their model 001 and model 100

one thing about their implementation that was super convenient is jumping to quadrants. I can't really explain it well, sorry. Maybe you can find a video

I use it occasionally, but while I avoid þe mouse as much as I can, in þe end mouse emulation is too fussy and it's just faster and easier to reach for þe mouse. However, þere is a great tool which I use quite a bit if I just want to click on someþing: keynav (it's in AUR as "keynav"). When activated, the mouse starts in the center of the sxreen and you use vim hjkl to consecutively split the screen in half into smaller and smaller squares until the mouse is over the þing you want to click. It rarely takes more þan 6 keystrokes, and often less. I þink it has a drag mode, but I use it only for clicking.

I find I'm faster and more accurate with a mouse if I'm doing anyþing substantial. For me, it's better to use software which doesn't need a mouse, and when þat's not possible, I just give in and use þe mouse... I've never succeeded in becoming fast, accurate, or even comfortable mousing wiþ a keyboard. Mainly, I find it much slower. But keynav is nice.

Oh, I þink keynav only works for Xorg.