RedDragon K585.
Although our title sounds like a Subway ad gone horribly wrong. It's at least honest about what you are actually getting, then RedDragons "Wired One-Handed Mechanical Gaming Keyboard", because if a person who recently lost their arm or hand was looking for a solution for full keyboard functionality in an ergonomic package for one hand. They would probably get frustrated really quickly seeing these things show up all of the time on Amazon.

This was just page 1 of 4! But we especially like the first one, which is just 'Fuck it, have a calculator'.
These designs are everywhere. Some of them stupid expensive, like Razer, where they add an analog stick to their keyboard. While the third parties are cheap. We managed to get ours from a computer closeout store for about five dollars. Now, for those looking for their own $5 deal. Sometimes, there are batches of these things released on eBay for a very low amount. So do not be discouraged. Nevertheless, after powering it up and testing, it appears to be totally functional. So sadly, no repair guide for this blog! But since we have it lets review this thing!
Continue onward into the diatribe if you dare.