Took some time to add a few more error diffusion based dithering to the #FFmpeg paletteuse filter: Sierra3, Burkes and Atkinson.
All the dithering in 1bpp can be observed here: https://imgur.com/a/2a1p4R8
Source images:
1. https://unsplash.com/photos/P4epudldYMU
2. https://unsplash.com/photos/iDNvparRZ2Q
Patchset is currently pending on the ml.
And here it is with 2bpp: https://imgur.com/a/yuX296Q