Working with Energy Types

[Lappy9000]

So I believe the default energy types in 3.5 are Acid, Cold, Electricity, Fire, and Sonic. Force is sometimes added in there too. Has anyone homebrewed (or know of a printed source) energy types that handle things like Water and Earth? I've seen a few sources that rate them as Slashing/Bludgeoning damage, but that doesn't really do it for me. I want to see if there are any other systems out there before trying to make my own.

[Dylaer]

IIRC, cold is supposed to correspond to water and acid to earth. I don't remember where that's from, but it makes as much sense as anything else. Strangely, I remember electricity being given as air, with sonic outside of the set of four, which is bizarre.

[Shadowknight12]

I do it like this:

Water: Cold and/or Acid.
Fire: Fire and/or Electricity.
Air: Force and/or Sonic.
Earth: Bludgeoning and/or Piercing and/or Slashing.

Basically, Earth rules over metals as well as sand and stone, so it gets more options to choose from, but the downside is that all of its damage is physical in nature, and therefore affected by DR (and it's not technically 'energy', so it's unaffected by energy resistance/immunity). Conversely, Air gets the 'energy' types with the least amount of resistances and immunities found in monsters.

For elemental choices, such as Elemental Savant, I allow the character to make his choice of energy/damage type (which means that you can have two Water Savants that use completely different manifestations of the element, one leaning towards acid and the other one leaning towards cold. Earth Savants get three possible manifestations, but they're all physical).