Arcane Bombardment + Temporal Manipulation + Mystic Speculation

Arcane Bombardment

Temporal Manipulation

Mystic Speculation

How it works

1. Cast Mystic Speculation with buyback by paying 2.
2. Arcane Bombardment triggers, exiling an instant or sorcery at random from your graveyard, and casting a copy of Temporal Manipulation without paying its mana cost.
3. Resolve Temporal Manipulation, causing you to take an extra turn after this one.
4. Resolve Mystic Speculation, causing you to scry 3 and return Mystic Speculation to your hand.
5. Repeat each turn.