This is a slim case for an iPhone 12 or 12 Pro (not the mini, not the max). I could not find a reasonable one online, so I made one myself. After 3 prototypes, I feel happy with this one. Side buttons have thinned walls so they flex nicely to allow you easy, tactile access to the side buttons. Camera bump is well protect. Corners all have added thickness because that is where a phone usually strikes when dropped (I've had many years of success with cases with exaggerated corners). The back of the case is a bit thicker by design to protect the phone, though it also helps in peeling off the printer bed.

The image of my prototypes is in black TPU, but obviously print in whatever color or material you'd like (though the case does have to bend and stretch a little to get a phone in so TPU is your best bet…I prototyped with PLA once and it was a comically bad experience).