Sanity Grinding
Zendikar was a set designed around the theme of explorers and adventurers discovering ancient secrets and powerful treasures. The set was packed full of treasures, literally – the Hidden Treasures promotion by WOTC inserted iconic, expensive and rare old cards into a small set of boosters. Players could open an Underground Sea or a Candelabra of Tawnos; they might open Guardian Beast or crack Black Lotus. Zendikar was full of treasures inside the set, too; the Allies were like Slivers, growing with every new one.
Eventide is packed with some expensive casual and tournament cards. The set contains many enemy-colored cards, from Lieges to filter-lands. The power of the lands, along with Reflecting Pool and the Vivid cycle, let people play essentially anything they wanted in decks.
The commanders in Innistrad all state they’re not dead. Jules digs to the bottom of this.