There's a couple other fields discussed before, so have a look at these:
http://www.pokemonreborn.com/forum/index.php?showtopic=13816
http://www.pokemonreborn.com/forum/index.php?showtopic=13530
Also, why not have the Inverse Field some people would like:
Inverse Field:
"The dimensions became twisted... and twisted... and twisted..."
- Type chart is flipped
- Hidden Power only does Normal or Psychic damage (Normal if Attack is higher, Psychic if Special Attack is higher, Random if equal)
- Trick Room, Magic Room, and Wonder Room last 8 turns
- Topsy Turvy doubles the stat changes when the stat changes are flipped
- Power Swap, Guard Swap, and Power Trick affect all Pokemon on the field
- Reflect and Light Screen raise the team's Attack and Special Attack instead of Defense and Special Defense respectively
- Normal and Psychic type moves get a boost
- Permanent Contrary (as suggested by SHIA)
And others...