And when we do that, you have to look at the keyword in terms of how many meaningfully different cards it represents
Laezel, Vlaakiths Champion Laezel, Vlaakiths Champion is one of the best ways to increase the number of energy counters you generate per source

3 Braska's Final Aeon Cecil, Dark Knight Cecil, Redeemed Paladin Chaos, the Endless Choco, Seeker of Paradise Cid, Timeless Artificer Clive, Ifrit's Dominant Cloud of Darkness Cloud, Midgar Mercenary Cloud, Planet's Champion Diamond Weapon Dion, Bahamut's Dominant Edgar, King of Figaro Emet-Selch, Unsundered Esper Terra Exdeath, Void Warlock Fang, Fearless l'Cie Firion, Wild Rose Warrior Freya Crescent G'raha Tia Gaius van Baelsar Galian Beast Garland, Knight of Cornelia Garnet, Princess of Alexandria Gilgamesh, Master-at-Arms Giott, King of the Dwarves Gladiolus Amicitia Gogo, Master of Mimicry Golbez, Crystal Collector Hades, Sorcerer of Eld Hope Estheim Hydaelyn, the Mothercrystal Ifrit, Warden of Inferno Ignis Scientia Jecht, Reluctant Guardian Jenova, Ancient Calamity Jill, Shiva's Dominant Joshua, Phoenix's Dominant Judge Magister Gabranth Kain, Traitorous Dragoon Kefka, Court Mage Kefka, Ruler of Ruin Kuja, Genome Sorcerer Lightning, Army of One Lightning, Security Sergeant Locke Cole Matoya, Archon Elder Minwu, White Mage Neo Exdeath, Dimension's End Noctis, Prince of Lucis Omega, Heartless Evolution Phoenix, Warden of Fire Prompto Argentum Queen Brahne Quina, Qu Gourmet Quistis Trepe Ragnarok, Divine Deliverance Raubahn, Bull of Ala Mhigo Reno and Rude Rinoa Heartilly

If you have a way to also discount your red spells, Birgi helps you even generate excess mana to potentially cast your whole deck
Its a very flavorful mechanic that can be banked for late game advantages or an early boost to power
Marketplace asks run higher, into the low $200s, so patience pays here