Blessing of the Oracle (Akroma's Will) If you're playing white in Commander, odds are you're running Akroma's Will
Happy ramping
When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1
Goofy Knight For A Day is Steeled to Prove his Mettle This heavy-hitting character serves as a massive threat that requires immediate attention from the opposing side of the board
You can actually target your opponent with it, potentially exacerbating a mana-light draw on their part, or sealing up a game on a crucial turn, when you just dont want them to draw a particular card for one or two more turns
There have been so many busted combo decks making use of Lotus Petal and Lions Eye Diamond, but my favorite will always be what I believe to be the most broken deck in Magic history (at least since the advent of the four-of rule and restricted list), a turn 1 kill deck detailed here , making use of the temporary abusability of Lions Eye Diamond when you could use it to play a spell from your hand before discarding your hand