My Air is still at level 10. I remember reading in the last tournament, you mentioned something along the lines that the single colours work well for you under certain circumstances and it is relatively cheap to raise them to level 15. So, keeping that in mind, I am planning to raise my Fire, Air, Water, and Forest to level 15 (and for strategic reasons, I save all that type of feeding until Leaderboard events).
The other level 15s I currently have are Rainbow Sentinel, Battlesteed, Gilded Knight, Huntress, Divine, Pyramid, Valiant, Diamond, and Gold Horizon. Generally, under "normal" battle conditions against Champions, my L15 Passion almost always wins on the first attempt and definitely on the second attempt. Under what I term "rigged" conditions where I know an extra difficulty factor has been thrown in, Passion won't be much good. For example, my first battle with Congo L20 back on 19-Jan, my Passion lost to it five straight times and I eventually took it down on the third attempt of using Infinity. My Passion's H2H to date with Congo L20 is pretty poor (i.e. 1-8).
My high-level dragons with yellow as a component are: Sunlight 14, Curio 14, Mage 14, Chronicler 14, Light Mother 12, Maple 13, Dusk 13, Music 13, King 12, Thoughtful 12, Adventure 12, and Surprise 12. Any suggestions as which other dragons to try?