Links to Download:
Wall mounted cell phone holder. I personally did this for my Samsung S8+ which has a case as well, so this specifically fit that pretty well. Though the result is something that can work/hold multiple types of phones securely, some with cases depending on thickness/width of the device.
The opening at the bottom is to feed a charger cable to which is centered for the S8+.
Could also be mounted on the wall with simply an adhesive of some sort instead of screws.