Each rarity level has distinct characteristics that affect how you should store and organize them: Advanced Organization Strategies For serious magic players and trading card collectors, moving beyond basic organization methods creates more efficient card management systems
Smothering Tithe Bolas's Citadel Jeska's Will Kinnan, Bonder Prodigy Ancient Tomb Mox Diamond Chrome Mox Mana Vault Lion's Eye Diamond Grim Monolith Yuriko, the Tiger's Shadow Winota, Joiner of Forces Gaea's Cradle Serra's Sanctum With little synergistic work, Gaea's Cradle and Serra's Sanctum produce insane amounts of mana
In the Arena announcement, Wizards describes Specialize as a brand new mechanic, so it seems highly unlikely that they only got one use out of it
Opened the Darksteel Transference deck and added cards from the Shards of Alara and Scars of Mirrodin blocks
It also deals some nice table-wide damage, which could be pretty significant in a Stun Counter-focused deck