Tiny measuring and marking-out tools
By: jarkmanFisher 150mm satin chrome rule
A really good little ruler. Flexible, high contrast, markings are very durable. Costs about 3 quid.
This one has been chopped down to fit in the flexure kit.
Kutsuwa 300mm folding rule
Because who doesn't want a long ruler in a short case ? Also functions as a sort-of set square, with detents at assorted angles.
Midori make something similar, too, in plastic or metal.
Midori XS tape measure
A 1.5m flexible fiberglass tape measure in a tiny, tiny package
Sharpest compass
A compass with a built-in 0.5mm mechanical pencil.
70mm vernier caliper
A tiny (and not very high quality)(but handy) vernier caliper. The jaws are not actually 100% parallel and the internal jaws are out by a third of a millimeter. I might fix that with a file. But, they did only cost a tenner from AliExpress. A very similar-looking model is sold by Moore and Wright for 25 quid, and that is probably better made and a better idea.