On my BMW R1100RT motorbike, the spark plugs are tricky to pull- there is so little room for getting a hold of the plug.

The "spark plug puller" (or "spark plug extractor") solves the issue.

Update 16.6. 2019: I managed to brake two sparkplugex trying to remove a really stuck plug. Therefore, I made the sparkplugex walls thicker and reprinted it with 100% infill.

While at it, I made the handle sightly larger so I can slip the finger in easier.

Update 26.6.2019: see the tube wrench extender that may be used together with this sparkplugex: https://www.thingiverse.com/thing:3715102