An interesting article, but it seems like quite an oversight to not even mention dithering techniques, which in my opinion give much better results.
I've done some development work in Pico-8, and some time ago I wrote a plugin for the Aseprite pixel art editor to convert an arbitrary image into the Pico-8 palette using Floyd-Steinberg dithering[0]
I ran their example image through it, and personally I think the results it gives were the best of the bunch https://imgur.com/a/O6YN8S2
I've done some development work in Pico-8, and some time ago I wrote a plugin for the Aseprite pixel art editor to convert an arbitrary image into the Pico-8 palette using Floyd-Steinberg dithering[0]
I ran their example image through it, and personally I think the results it gives were the best of the bunch https://imgur.com/a/O6YN8S2
[0] https://github.com/aquova/aseprite-scripts/blob/master/pico-...