Ask HN: Are there any keyboard extensions easily attachable on a laptop?

I don't mean external numeric keypads, my laptop already has that (and never used it). I mean just a few extra modifier keys (control, alt, super, etc) which can be easily attached on a laptop and reachable by thumbs.

Take a look at the thumb keys of keyboard.io and you know exactly what I mean.

This would be very useful for programming especially in editors such as Emacs, where you want your fingers to stay on the home row for faster typing but avoid using the small fingers to prevent RSI (Repeated Strain Injury).

I've tried remapping the keys to move all the modifier keys closer to the thumbs, have tried some hacks with input-remapper [1] to redefine the keys for short-presses, long-presses, hold etc. and have tried Emacs key-chords. But I think nothing would beat having just a couple of extra keys reachable by the thumbs.

Alternatively, are there any laptops which have such keyboards with extra modifier keys?

[1] https://github.com/sezanzeb/input-remapper