I liked the cable holders that people have uploaded to Thingiverse, but I found that cables with large plugs would slide off, especially when the holder was mounted vertically.
This is my revised version, with a wedge cut out of the typical design to better hold the "plug" portion. The photos show it mounted in my car. The white tab sticking out of the side is a Command adhesive strip, in case I wanted to remove it later without messing up my dashboard.
Prius_cable_holder_v2.stl | 81.6KB |