I've used a large syringe for many jobs, I have two converted broken machine hacksaw blades reconfigured, one as a scraper the other as a scriber. A welding rod for poking stuff.
Plastic medical locking tweezers for holding items together, good for holding parts together when gluing or wanting small items to set after applying sealer etc.
Assortment of old takeaway plastic containers. Useful for putting bits of bike as you strip it down e.g. one for bodywork fastenings, one for engine parts etc. Stops you having to hunt for things as you put them back together. Also loads of offcuts of wood. Spread the load on jacks when lifting, chock wheels to stop movement, lift a wheel to get an axle in easier etc. etc. It is a tool but I still can't believe how few people seem to have a spring puller. Oh, and a kettle, you can't work without tea!
Bit's of wire and a bulb. Makes a useful volt meter, sort of. Talcum powder. Can help find where that little leak is coming from. Chemical metal. Last resort emergency fix for all sorts.
