I'll also plug an invention of my own: error diffusion with a random parameter in the diffusion matrix, keeping the sum of weights constant (and equal to 4/5, so boosting contrast slightly).
I came up with this for a Code Golf challenge a few years ago, personally I think it looks really good. I haven't seen it elsewhere.
Disclaimer: yes I like to write ugly Fortran code for fun (and profit).
That is a very elegant trick, I love it! I wonder what comes out of that when applied to a flat grayscale image - perhaps it leads to a decent blue noise pattern, or an approximation of it? EDIT: The reason I'm half-expecting that is because semi-randomizing the diffusion matrix reminds me a bit of Bridson's Algorithm, in that it mixes constraints with randomization[0].
And kudos for sticking to the programming language you love and feel comfortable in :)
EDIT: Something I never noticed before: a black and white dithered image causes flickering when scrolling on an LCD screen, as least on mine, and it amplifies regions with patterns, like the checkerboards in ordered dithering, or the regular artifacts like in the example image of the challenge.
However, your "randomized Sierra Lite" version seems to mask that flickering: it's still there, but feels much more like white noise that is relatively easy to ignore.
I came up with this for a Code Golf challenge a few years ago, personally I think it looks really good. I haven't seen it elsewhere.
Disclaimer: yes I like to write ugly Fortran code for fun (and profit).
https://codegolf.stackexchange.com/a/26569