Yenna, Redtooth Regent + Agatha's Soul Cauldron + Ashnod's Altar + Hyrax Tower Scout

Yenna, Redtooth Regent

Agatha's Soul Cauldron

Ashnod's Altar

Hyrax Tower Scout

How it works

1. Activate Hyrax Tower Scout using the Licid's ability by paying its activation cost, attaching Hyrax Tower Scout to Yenna and causing Hyrax Tower Scout to become an Aura.
2. Activate Yenna by paying 2 and tapping it, creating a token copy of Hyrax Tower Scout.
3. When the Hyrax Tower Scout token enters, it triggers, untapping Yenna.
4. Activate Ashnod's Altar by sacrificing the Hyrax Tower Scout token, adding CC.
5. Repeat from step 2.

This clever engine turns Yenna, Redtooth Regent into an endless cloning factory by turning Hyrax Tower Scout into an Aura—likely via another card's effect—so that every token copy she makes triggers her self-untapping ability. Once the Hyrax Tower Scout token enters the battlefield and untaps Yenna, you can feed it to Ashnod's Altar to generate the colorless mana needed to fuel Yenna's ability again. Meanwhile, Agatha's Soul Cauldron lurks in the background, making sure your mana costs and activated abilities can be paid smoothly across your creatures with the help of its versatile graveyard-exiling and counter-distribution.