finder

noun3

1. •
   One who finds or discovers something; a discoverer.

   • Finders keepers, losers weepers.
2. •
   (UK, historical) A person who picks up scraps and oddments to sell to make a living.
3. •
   A device, such as a viewfinder, used to locate a target or other object of interest.

   • Perhaps some electrical finder could have been developed so delicate that it could have located the source of all this spreading joy and fortune. — 1945