If you own a Toyota RAV4 (5th model, 2019 onwards) and feel the need to mount anything to your dashboard, look no further: Here's a simple no-tools-needed mounting clamp that slides nicely around the dash cushions just under the side air vents and is strong enough for your everyday phone, garage door remote, picture frame - whatever.
The clamp installs on the car, the mounting plate clicks on to the clamp - bingo! If you feel it is too thin, scale it - sideways only, since otherwise it won't fit any more. You knew this, didn't you?
But ... wait ... just how do I ... ??? Easy: Since you're here you're into making things - good! Just design a custom case for whatever you want to mount, marry this case with the mount plate (in any 3D software that handles .stl or .step files) and you're done.
Mounting: Mount from below, i.e. hook the 90° side of the clamp between cushion and dash body, then push on the upper part until it snaps between cushion and vent frame and you're done.
Printing: use PETG since in cars you might expect higher temperatures than what PLA could handle. Print the clamp lying on the side to ensure strength due to the layers nicely go along the clamp to carry the load and not to worry about layers becoming detached - they won't. As for "your" case / hook / whatnot - print in a direction that covers for the forces the case has to take up.
Update : If you rather rely on screws than click solutions there's new parts for standard M3 screws and nut, both .stl and .step