Other possibilities ...

- Repairing a big nail hole in a tire tread (but not until you get the bike home and let it cure for a day).

- Making "handles" for your $5 park cone wrenches.

- Those black inserts in Dura Ace brake caliper cone nuts. Or maybe the same use with Huret rear derailleurs.

- Custom pedal dust caps.

- Finishing tape for bar tape. wtf? Now i'm really reaching. lol.