Well Grass is kinda control, talking to plants, etc.
Bug is talking to insects, controlling them, etc. as well.
Poison is a little tricky. It does give immunity, but you can also turn something into poison, make it poisonous, if you have high Aura. Also gas clouds. I'm working on poison.
Ghost is like seeing the dead, spirit world, also killing things, and in some cases seeing the past. Ghost is the most confusing.
Fighting is pretty much what you would think it would be, also enhanced muscles and limitations have a higher limit.
Rock...is confusing. Rock would basically have you control rocks, and make'em appear out of the ground.
Electric is kinda like being a Sith, control over electricity.
Steel is like a harder Rock, also the ultimate defense.
Ground would allow you to control the earth itself, sense things through it like Toph in Avatar.
Dark can have you see in the dark, become one with shadows (like enter "the Shadow Realm", but not what you would think), and a bunch of other things once I get into it.
Psychic can also have you read minds, move stuff, and influence others. Also see future, or predict certain things.
Ice can have you manipulate the temperature of the area, cool things down, etc.
Does this help, or do you need more?