Panels like this have been available on Waveshare for a while. They are fairly inexpensive (sub $100 range) but the refresh time is super slow. For example:
You can also order many of the same panels directly from the online store of the E-ink company BTW. Not that the prices there are very nice. But it's useful to look up parts and then search for other distributors.
https://www.waveshare.com/product/displays/e-paper/7.3inch-e...
Looks nice, but the full refresh time is like 30s.