Codie, Vociferous Codex + Filigree Sages + Training Grounds

Codie, Vociferous Codex

Filigree Sages

Training Grounds

How it works

1. Activate Codie by paying 2 and tapping it, adding .
2. Activate Filigree Sages by paying , untapping Codie.
3. Repeat.
4. Once you have an arbitrarily large number of Codie triggers, you may cast any instant or sorcery spell by paying its mana cost.
5. Codie triggers for each time you activated its ability.
6. Resolve the first trigger, causing you to exile cards from the top of your library until you exile an instant or sorcery spell with lesser mana value, and allowing you to cast that spell without paying its mana cost.
7. Repeat step 6 for each remaining trigger.
8. You may also repeat this combo for each instant and/or sorcery card in your hand, and on subsequent turns.

This loop turns Codie, Vociferous Codex into an explosive mana-generating engine by using Training Grounds to slash the activation cost of Filigree Sages down to just a single blue mana. Because Training Grounds makes the Sages' untap ability cost only {2}{U} minus {2} (which floors at one mana), tapping Codie to generate five distinct colors of mana allows the Sages to untap the Codex with mana to spare. Repeating this process yields an arbitrarily large amount of colored mana and triggers Codie's cascade-like ability over and over, letting you dig through your library and cast every single instant and sorcery you find completely for free.