The lieges from Eventide had enemy-colour costs and the Horror creature type Deathbringer Liege, Mindwrack Liege, Murkfiend Liege, and Balefire Liege, Creakwood Liege
The Elder Dragon sees play in a variety of MTG Commander decks like The Ur-Dragon and Miirym, Sentinel Wyrm
The upside of killing something relevant and tempting can absolutely win games in UR, but to do this your opponent has to have multiple creatures of similar size on their board, which is often a board state that is not favorable for you
The art puzzle/marketing card that is included in each booster pack now has a puzzle piece image on one side and a piece of the story lore on the back
If consistency or winning are your primary goals, playing as many efficient tutors as you can fit in your deck is generally good advice
Instead of the usual Rotation and Renewal cycle happening in September, Wizards is delaying proceedings by one year