Delney, Streetwise Lookout + Mox Amber + Dream Stalker + Cheering Fanatic

Delney, Streetwise Lookout

Mox Amber

Dream Stalker

Cheering Fanatic

How it works

1. Declare Cheering Fanatic as an attacker.
2. When Cheering Fanatic attacks, it triggers, allowing you to choose "Dreamstalker" and cause spells with that name to cost 1 less this turn.
3. During your main phase, cast Mox Amber by paying 0.
4. Activate Mox Amber by tapping it, adding one mana.
5. Cast Dream Stalker by paying one mana.
6. When Dream Stalker enters, it triggers twice due to Delney, returning Mox Amber and Dream Stalker from the battlefield to your hand.
7. Repeat from step 3.