From OSP Wiki

While Open Source is mostly about programs, sometimes hardware choices limit our options when working with Free and Open Source Software. The focus here is not on the quality of the hardware but on it's support by (and of) open source programs and operating systems.

Cameras

Scanners

Linux drivers for Epson scanners 

Epson provides Linux drivers (GPL, LGPL, EAPL and some proprietary) for most its scanners through home Epson Avasys Corporation. The drivers work as SANE backends.

Printers

Linux drivers for Epson printers 

Epson provides Linux drivers (GPL, LGPL and EAPL) for most its printers through Epson Avasys Corporation. The drivers work as CUPS backends.

Tablets

Graphics tablets with Linux 

Discussion on the Open Source Photography group on Flickr.

Calibration tools

Monitors