term:

Finder

finder n

1 : one that finds [the of lost property has a right to it as against the world, except against the true owner “McDonald v. Railway Express Agency, 81 S.E.2d 525 (1954)”]
2 : one that for a fee discovers a financial opportunity, passes it on to another, and may act as a go-between for but does not participate in subsequent negotiations between the involved parties compare broker