What a coincidence, I just stumbled upon this article a few hours ago while trying to find out which error diffusion algorithm is used by Photoshop out of curiosity.

I've been playing with dithering recently to create braille art[0] and this series of articles[1] by the libcaca developers has been a huge help. It also goes over model based dithering algorithms which tend to give the best results.

[0]: Example https://pastebin.com/raw/cRt4GL8j

[1]: http://caca.zoy.org/study/index.html