The idea of a "Blender" expansion to build off the mechanics of the other expansions has been tossed around, and I think I figured out how to make a portion of it work:
Cards like mythos. gates, locations and what not would have a compatibility icon in the bottom left, opposite the expansion symbol. For instance, a location card for Riverside on the main board has an encounter at the Unvisited Isle that draws an innsmouth look card and a Riverdock encounter that can gain an Exhibit item. In the bottom left, there is a "C:" (or whatever) followed by the Innsmouth and Dark Pharoh symbols. Then, you can just got through and add all the cards from the Blender that match with the particular expansions you're using at the time.
Also, it should include the Dark Pharaoh and Black Goat Heralds printed... Just sayin'.
