Fortune Hunters
Fortune Hunters is a book of non-player characters that may be encountered in any town. Each of the NPCs is detailed at three different points in their history: low level, medium level, and high level. They can be used as recurring allies or villains with ready explanations of what they have been doing since the last time the characters encountered them.
The backgrounds of the NPCs assume that the book is being used in tandem with the Cat's Cradle Sourcebook published by Frog God Games, but can be used in any setting.