I won't really be able to help to identify the valuable ones as I'm not an effects enthusiast myself, but each transistor should be marked with its part number. I would suggest sorting them by part number and then making a post about them on diystompboxes.com, someone will probably make you an offer to buy them in batches as each one of the same part number will have slightly different characteristics and produce a slightly different sound. Enthusiasts like to sort through a batch and pick out the best ones; for some circuits they need to match up a pair with similar characteristics. It will be a good idea to state that they have verifiable provinence to establish authenticity as there apparently some are fakes around.
