they are used in auto body panel replacement fairly often for inner and outer quarter panels , around the wheelwell. and they are great when plugwelding sheetmetal ,a as the clamp holds pressure at both edges of the plug hole.
looks like aircraft sheet metal tooling for setting and removing rivets
do a google search for yard store .com you can i.d. almost everything you have pictured
hello. dont know if they are still made but years ago you could by dry transfer rub on lettering in very small sizes in the office supply stores..maybe still an option
check out urrea (the old mexican proto) i bought a 5 pc. metric half moon set for 54 dollars american. the wrenches aren"t finished as nice as american proto but fit the fasteners well and seem plenty strong.