Scrap Trawler + Krark-Clan Ironworks + Salvaging Station + Walking Ballista

Scrap Trawler

Krark-Clan Ironworks

Salvaging Station

Walking Ballista

How it works

1. Activate Krark-Clan Ironworks by sacrificing the nontoken noncreature artifact, adding CC.
2. Scrap Trawler triggers, returning Walking Ballista from your graveyard to your hand.
3. Activate Salvaging Station by tapping it, returning the noncreature artifact from your graveyard to the battlefield.
4. Cast Walking Ballista by paying 0.
5. Walking Ballista enters the battlefield and dies as a state-based action due to having zero toughness.
6. Scrap Trawler and Salvaging Station trigger.
7. Resolve the Salvaging Station trigger, untapping itself.
8. Resolve the Scrap Trawler trigger, returning nothing from your graveyard to your hand.
9. Repeat.
10. Once you have infinite mana, you may use it to cast Walking Ballista, and then remove infinite +1/+1 counters from it to deal infinite damage to any target(s).