Sorry to bring up old settlings, but I've thought of some interesting ideas.
These ideas aren't too game-breaking that people will start taking dragons left and right, these are just abilities that are similar to any other, in that they are unique. (figure that one out)
Azure Dragon: Swift: Physical damage reduced by N. N= the total number of airborne creatures you have divided by 2.
Black Dragon: Stealth: Spells that damage Black Dragon have N% chance to miss. N= the total
quanta you have, divided by 3.
Crimson Dragon: 2
Spread: Target Fire creature gains +2|+0. Crimson Dragon gains -2|-0.
Ice Dragon: 2
Chill: Target frozen creature gains -2|-0.
These are just a few. I'm not up for letting this die yet.