Warden of the Beyond is... interesting. Too bad that even if you do manage to exile one of your opponent's cards, this isn't very good.
Soul of Shandalar looks to be the most playable of the Soul cycle so far, and has great art in any case.
Return to the Ranks is pretty cool. I like how with convoke, you can use it to essentially double your army.
I really do like when sphinx cards have actual riddle elements with them.
Neat flavor, but the card is eh.
It's really neat to see Ob Nixilis again, though I wonder if the use of that character in particular was requested by Brad Muir or if that decision was made by the creative team.
Aggressive Mining is neat in how it can potentially be very powerful, but very easy to misuse and screw up with.
Goblin Kaboomist is great.
Yisan, the Wanderer Bard is pretty interesting.