The Project Z is a new attempt at bringing back the classic PDA form factor. Built around a Raspberry Pi Zero 2 W, the Project Z runs Linux and should eventually be released for under $100.https://www.notebookcheck.net/Project-Z-hopes-to-release-compact-PDA-lookalike-running-Linux-for-under-100.855046.0.html
Well err... not exactly 'PDA' but rather 'Netbook'.
While the classic PDA's screen generally was from < 3" up to 5-6" the devices that were 7" - 12" fell into the "Netbook" camp.
PDA's may (or not!) have keyboards and were always touch screen while Netbooks just about never had touch screens and always had keyboards.
PDA's almost always could fit in a breast shirt pocket.
OBS computing devices pre "smart phone" and "tablet".
Modern devices ability to translate dictation has evolved to the point where a keyboard on many devices is no longer essential.