Here are some ideas...none of them are really that creative, but they could make things interesting: 
1. Infinite jumpjets.
2. Can jumpjet multiple times in midair.
3. Vehicles have infinite boost.
4. Replace ranger/tech/gunner skins with three different skaarj skins.
5. An RPG-type mutator where points act as experience, and you gain levels and become progressively more powerful as you gain points. You would decrease in level as you lost points.
6. Low gravity (like Freefall).
1. Infinite jumpjets.
2. Can jumpjet multiple times in midair.
3. Vehicles have infinite boost.
4. Replace ranger/tech/gunner skins with three different skaarj skins.
5. An RPG-type mutator where points act as experience, and you gain levels and become progressively more powerful as you gain points. You would decrease in level as you lost points.
6. Low gravity (like Freefall).