Arcbound Reclaimer + Showdown of the Skalds + Urza's Bauble + Madame Web, Clairvoyant

Arcbound Reclaimer

Showdown of the Skalds

Urza's Bauble

Madame Web, Clairvoyant

How it works

1. Cast Urza's Bauble either from your hand or from the top of your library by paying 0
2. Showdown of the Skalds triggers, putting a +1/+1 counter on Arcbound Reclaimer.
3. Activate Urza's Bauble by tapping and sacrificing it.
4. Activate Arcbound Reclaimer by removing a +1/+1 counter from it, putting Urza's Bauble from your graveyard onto the top of your library.
5. Repeat.

This clever loop turns zero-mana artifacts into an endless engine by recycling them right back to where you need them. Madame Web, Clairvoyant lets you cast noncreature spells like Urza's Bauble straight off the top of your library, while Showdown of the Skalds provides the crucial +1/+1 counters each time you cast a spell to replenish Arcbound Reclaimer. You then use Arcbound Reclaimer's activated ability to strip that counter and put the sacrificed Urza's Bauble right back onto your library, setting up the exact same draw and cast again and again.