Since I am also interested in this topic for personal reasons, I have searched all the support pages of the (ex-)manufacturers of graphics tablets mentioned to me by my trusted search engine for information on drivers for Linux (Ainol, Aiptek, Amazon, Gaomon, Genius, Huion, IGERESS, Intey, KURIO, Lexibook, Odys, Perixx, Trust, Ugee, Vtech, Wacom, XP-Pen (some manufacturers seem to no longer exist)). There are only two companies that offer linux drivers for their graphics tablets!
The company Ugee offers Linux drivers exclusively for their model M708 for the following distributions: Ubuntu, Manjaro, Arch, Debian, elementary OS, Mint, ezgo Linux, Pop!_OSan, Centos, Fedora, Red Hat, OpenSUSE, Mageia (and of course for Windows and Mac).
And XP-PEN offers linux drivers for very many models, I didn’t search the whole support section because there are just too many models.
But, provided some self-initiative / own effort, it is obviously possible to run much more graphics tablets under Linux. ->->
Also worth a look at the pages and lists of the DIGImend project.
Michelist