Board Thread:Questions and Answers/@comment-26021514-20160504041212/@comment-28002443-20160507141145

Sound could be interesting. Maybe a character has air, and sub-element sound, they could use the ability to communicate with others in the team. For example, they could use a large wind to give the others cover and then send a message through the wind to communicate with allies.

Another option is gas. Maybe they can control air (oxygen) but they can also control a variety of unhealthy gasses and fumes. Or perhaps, to make it interesting, they can only control one (propane, carbon dioxide, etc)

Hope I helped. :) Good luck!