The newest Sarkhan planeswalker is a true gem for Limited players. The best part is the plus one ability, which protects Sarkhan from losing loyalty counters if attacked, since he becomes a dragon creature. If you control other planeswalkers, they become dragons, too.
The minus three ability puts dragon tokens on the battlefield, and it's easy to repeat it in just two turns.
The passive ability is also very good, but is most likely designed for Standard rather than Limited. But in any case, Sarkhan the Masterless is a blast if you can find it in your pool.