Couple of small but cool doodads I had in the day......

1. Tire saver. Ther were small rings of wire that mounted onto your brake caliper bolt and rode on top of the tire to help clean off debris.

2. Back in the day of toe clips we would point the toe clip down and use it as a kick stand. Problem was the bike would roll and fall over. Someone came up with this little device that mounted under the bottom tube that when flicked down, would keep the front tire from rolling and the bike from falling.

Not exactly CNC type of stuff but they popped into my mind.