This is an incremental update to my earlier design (https://www.thingiverse.com/thing:1323186) with improvements as suggested by @carty2560. The fundamental improvement is a more substantial footprint for improved stability - with the addition of non-slip material, the stand should stay in place and avoid tipping over when the phone's touch screen is used while sitting on the cradle.
I designed this thing for my Samsung Galaxy S6 smartphone with an inexpensive, generic Qi charging pad. My specific pad was branded the Audew Q5 (http://www.banggood.com/AUDEW-Q5-Universal-Qi-Wireless-Charger-Charging-Pad-Transmitter-p-985122.html). Most other cases (or bare phones) should fit as well.
The design is generic enough so that almost any smartphone will fit mechanically, although I can't guarantee that the charging pad will be positioned correctly for models other than the S6, the S7, and the S8 (my current phone).
Apply a non-slip sheet material (cork, foam rubber, etc.) to the bottom of this thing to improve stability and to protect delicate table surfaces. I used something similar to this: https://www.amazon.com/dp/B002JTRNIW