Most E-ink devices are B&W, usually multi-shade greyscale, with higher-end devices being 16-shade. Dithering or halftoning gives quite good results on images.

There are some colour devices, though more usually ebook readers. Colour is muted -- more pastel than saturated, but gives some distinction for manga or color-differentiated graphics.

Video review of the Onyx BOOX Nova3 Colour: https://yewtu.be/watch?v=aSUcnkQCa-s