Sunforger + Final Fortune + Angel's Grace + Mistveil Plains + Deserted Temple

Sunforger

Final Fortune

Angel's Grace

Mistveil Plains

Deserted Temple

How it works

1. Activate Sunforger by paying and unattaching it, searching your library for Final Fortune and casting it without paying its mana cost.
2. Resolve Final Fortune, causing you to take an extra turn after this one and lose the game at the beginning of that turn's end step.
3. Activate Mistveil Plains by paying and tapping it, putting Final Fortune on the bottom of your library from your graveyard.
4. Activate Sunforger's equip ability by paying 3, attaching it to any creature you control.
5. Move to your next turn.
6. Activate Sunforger by paying and unattaching it, searching your library for Angel's Grace and casting it without paying its mana cost.
7. Resolve Angel's Grace, causing you to be unable to lose the game this turn.
8. Activate Mistveil Plains by paying and tapping it, putting Angel's Grace on the bottom of your library from your graveyard.
9. Activate Deserted Temple's second ability by paying 1 and tapping it, untapping Mistveil Plains.
10. Activate Sunforger's equip ability by paying 3, attaching it to any creature you control.
11. Repeat.