Trade Fodder is any epic or rare that is typically not the best, or is simply a fighter you don't wish to max out or work on. Some examples of Trade Fodder may include heroes from dungeons who aren't so good without their edge, most pixite/voxite or premium build epics, or even sometimes the rewards from bracket battles in PvP events. Usually you can get some decent trades using trade fodder such as trading the not so useful Kastubili for something such as Ogiva. Sometimes you have to pay double such as trading 2 Adrahasis for a single Ira, Hypnotic Specter. Spotting a good deal using the Search for Terms button with a trade fodder epic is how you get ahead of the game. So it might not always be a bad Idea to sit there refreshing that Mirza because you never know when you might catch a 1/5 Amaralice asking for it.