Here are some good combos:
electric type+ dragon more than 1600 is the twin headed thunder dragon(2800-2100) Its really cool
any dragons fused with time wizard is The thousand dragon (2400-2000) cool.
And the coolest there is a magic card named Dian keto the cure master that costs 999999 starchips. If you know the way to get 999999 starchips you could buy it.
Buy two then fuse them together and it will be megamorph. The code for the magic card is 84257639.
If you know the cheat of infinate starchips (sorry about my spelling) and how to pause the game please post here.