Paper monitor, but the hardware designs for this one are entirely open source.
"The Modos Paper Monitor is an open-hardware 13.3-inch, 1600 x 1200 monochrome or color e-ink monitor with a fast 60 Hz refresh rate, low latency, multiple image modes and dithering options, and flexible screen update control. It can be connected using HDMI and USB-C and works on Linux, macOS, and Windows."
There's a link to a document below that explains everything you ever wanted to know about paper monitors and e-ink.
