Unfortunately I do not know of others. Are you looking to buy or sell? FW or SW? There is always Craig's List too. For selling rare FW fish AB is great, prices can get really high, especially if you are willing to ship to Japan. For selling gear I still like ebay unless I want to put a high reserve because Ebay makes me pay whether I sell or not. I have sold on ebay at astronomic losses but I do get good deals off it so it evens out. I don't know if anyone is using yahoo, doesn't seem to get much action.
Kate