After a few years I'd gotten dissatisfied with my previous Wacom easel at https://www.thingiverse.com/thing:349973, and instead of trying to fix it I decided that I wanted to try a different design this time, one which is much more minimal and easier to print and install. And this works really well!

Basically, you mount these two hooks to the front of your desk (using screws or double-stick tape or the like), and then put something solid and heavy behind them to prop the tablet up on (I use an old USB peripheral switch and a nonslip rubber mat). You can then adjust the angle of the tablet by moving the object.

These also double as desk-mounted storage hooks for headphones and the like. Consider the possibilities!