Finders are afterlights who specialize in locating items that have crossed into Everlost. Speedo is an example of a Finder.
Finder Types Edit
It would appear that there are various different kinds of Finders, although not a lot of specificity is brought to this. Based off the fact that Mary refers to Speedo as a Food-Finder, it can be assume that the different types are based off of specialties.
Allie becomes a Finder of sorts in the second book when she travels Everlost with Mikey.