Quick view:
Minotaur Exploroer
Rotting Giant
They are still 3/3s for 2 mana, they will see play. The Minotaur can go right into almost any aggro build (discard Roar of the Wurm hopefully), the Giant needs a little more help but definitely isn't bad.
Cephalid Colosseum
Cabal Pit
Petrified Field
They aren't as good as the Barbarian Ring, but the Pit can get rid of alot of annoying creatures that can give black fits (like the Voice of All) and the Colosseum is a great late game filter card: sac the land, dig 3 cards deeper into your deck, discard the chaff and extra lands. The Petrified Field isn't that great in that it is dependent on the sac lands to be in the deck, but it isn't horrible and can be annoying. Personally I like Deserted Temple better, but that's more for casual reasons.
Thought Devourer
Upheaval
These 2 are already in a solid deck together. Its an new skies deck with the key card being Spellbook, which makes both of these cards much much stronger. Upheaval is a powerhouse in and of itself, it might be tough to use but its way too strong an effect to ignore.