Olivia, Crimson Bride + Medomai the Ageless + Phyrexian Altar

Olivia, Crimson Bride

Medomai the Ageless

Phyrexian Altar

How it works

1. Declare Olivia as an attacker, attacking an opponent unable to block your creatures.
2. Olivia triggers, returning Medomai from your graveyard to the battlefield tapped and attacking that opponent.
3. Deal combat damage with Medomai, triggering its ability, causing you to take an extra turn after this one.
4. Activate Phyrexian Altar by sacrificing Medomai, adding one mana of any color.
5. Repeat.