Say I wanted to only fuzz with alphanumeric characters or specific strings with boofuzz. Is there a way to force this behavior? In sulley you can make a file named .fuzz_strings that I think does something like, is there something similar to this in boofuzz?
I don't think there is a built-in way to fuzz from a specific list of characters or strings. To make it yourself, you could extend BasePrimitive. See boofuzz/primitives/string.py for an example.
You can also open an issue and make a feature request on the Github repository: https://github.com/jtpereyda/boofuzz/issues