Prognostic sphinx is a great blocker with the five toughness as well as really solidifies your late game with the scry three, and the
Citadel siege is amazing against the aggro heavy meta. It really shuts out abzan and mono red. With abzan, tapping down their
siege rhino is great or just for opening up a hole for something like rabblemaster, and against other aggro decks or any other deck in game one turning your sphinx into a 5/8 then an 8/11 or making a soulfire huge for crazy lifegain almost always equals a win