I'm about to submit my latest product idea to Quirky: RATTLESTOP. It's an elastic band that wraps around a door edge at the strike, and stretches over the door handles to stay in place. It has small pads on either side that compress between the door and the jamb to stop the door from banging and rattling. And it probably should be clear, to be as unobtrusive as possible.
Here's what I've got. I made the band in two halves (later joined), by lofting. I couldn't find any way to twist and scale a profile along a 3D spline, so I manually scaled, placed, and rotated lofting sections along the spline to form the part that goes around the knob. After a lot of futzing, it came out OK, and the TPE material is decent. A physically-based, collision detection, math-based solution would sure be nice...! This is REV5. It gets the point across. Vote for them making this, starting Tuesday on Quirky. Will post a link.