ok elemental heros are only for fun because they rarely ever win against good decks. dragon decks can get very expensive and are usually border line good but they can be really good but it will cost more then you are probably willing to spend. Dinosaurs are a no because there arent enough good dinosaurs to play around, now there are some very good dinosaur cards but only build this deck if you are playing for fun just like the elemental hero's. a random deck is a no because random usually means no strategy and every deck needs a strategy. i would suggest a fiend, warrior, machine, or spellcaster deck.