Matias has a neat one-handed keyboard. It's quite expensive for what it is, especially considering these days where it's so easy to get a keyboard with remappable keys. There's a simulator on the sidebar at the link, and IMO it's quite intuitive.

https://matias.ca/halfkeyboard/

I tried that concept whith my ergodox when i had an arm in a splint, but i couldnt quite get my brain to wrap around it. I could type on the right key, but not press the mirror/switch key at the right moment.

What would have made it easier is if it could infer the right key like an autocorrect

Wow, 595 USD is insanely expensive for literally half a keyboard.