For Winter Orb, this will be artifact and creature sources of mana that continue to untap regularly, or a way to tap the Winter Orb so that it's not untapped when your turn rolls around, and you aren't effected by it, like Urza, Lord High Artificer or Derevi, Empyrial Tactician or the new Galazeth Prismari (there's no rule that says you can't generate mana you can't spend, and if you think this is a hint about a forthcoming article, then, you're right) A Stax deck will also need a win condition, since it's not enough to merely grind the board to a halt
Youll fill your deck with high-toughness creature cards like 0/7 walls or something like the 0/17 Charix, the Raging Isle
the risk of not having Flame Swordsman and Flame Adept for Flame Seraph makes the deck a bit luck-based without the proper support
With the menacing Giovanni in the foreground, and the awesome Mewtwo softly pulsing with Psychic energy in the background, looming over you, it has quickly become the most valuable modern Mewtwo ever printed