Gandalf, White Rider is excellent for various creature-heavy decks due to its ability and color identity, like green-white token decks and even mono-white go-wide decks with Darien, King of Kjeldor
Triggered abilities use the word "when," "whenever," or "at." They're often written as "[Trigger condition], [effect]." Some keywords (such as prowess) are triggered abilities and will use "when," "whenever," or "at" in their reminder text
You don't have to reveal a drawn card with miracle if you don't wish to cast it at that time
But she seems bad, and shes also in blue, so splashing for a 2-drop super mana dork seems bad
3 Tempt With Discovery Another card that provides tons of asymmetrical benefits to you and your opponents is Tempt with Discovery