I would like to self-nominate dithr, a buffer-first dithering and halftoning library designed around typed mutable slices. Features include explicit stride-aware image handling, Gray/Rgb/Rgba support across u8/u16/f32, palette/indexed workflows, and optional image adapters. There are implementations of essentially every major deterministic modern dithering and halftoning family in practical use (64 different dithering/halftoning methods).