Nuts and Bolts

[blue chim]

What I am trying to get to is what are the wrench sizes everyone can think of that are needed imperial or metric to work on the Chim?
Are there any non standard ones I may come up against? This popped into my head cause changing the belt tensioner, I discovered an imperial one fixing it on.
Also, I have lost my 10mm flexible head ratchet wrench any idea what the best place to buy one from is? Got the others in a nice set.