So your choices are:
1. Beat Solteris 1-7 progressively unlocking more powersources as you go.
2. Beat Bloodmoon 1 OR 2 which = Solteris 1-5. This unlocks everything but Ethereal, Elemental, Metal, and Death.
3. Beat any of: Bloodmoon 3, Big Bynn, Deepscar, any Steam Factory, Bimbalicus, any MMM, any Crystallos, any SoD raid. This unlocks every powersource.
Any non-raider should be able to throw together a few groups for Bimbalicus and unlock every powersource.