Like DanteRotterdam says, if the GM adds in the benefits you can make a lot of use of Knowledge skills.
Make a Streetwise or Knowledge (Underworld) check to find a fence to sell your goods. A more successful check can find a fence who will pay more or be more discreet.
In Dante's example with the Gorax, you could possibly gain Boosts on checks against the Gorax if you're trying to fight it or trap it. If you know where it's going to be because you know its feeding habits, you can trap it more easily.
I've designed an encounter where the PCs are fighting Aqualish thugs in a town square with food vendors. A Xenology check could tell them details about Aqualish biology. "If you can knock over this food cart, the smoke will irritate the eyes of the Aqualish and blind them."