Karn, Silver Golem + Salvaging Station + Phyrexian Altar

Karn, Silver Golem

Salvaging Station

Phyrexian Altar

How it works

1. Activate Karn by paying 1, causing any noncreature artifact with mana value one to become a 1/1 artifact creature until end of turn.
2. Activate Phyrexian Altar by sacrificing the artifact, adding 1.
3. The artifact dies, triggering Salvaging Station, untapping Salvaging Station.
4. Activate Salvaging Station by tapping it, returning the noncreature artifact from your graveyard to the battlefield.
5. Repeat.