For Yshtola, it came down to a mix of popularity of the character as well as being a spellcaster, her story and character development offered a wide range of abilities and moments to pull from to lead the deck
There are two imporant things to note about reducing the harmonize cost this way: You can only tap one creature per card harmonized
The versatility it offers of searching up any number of creatures with a total MV of 6 or less makes it shine as one of the best toolbox-openers in the game, grabbing you that Endurance and Reclamation Sage at the same time to permanently shuffle away that damn Sphere of Safety
Tiamat is a gigantic dragon whose five heads reflect the forms of the chromatic dragons she createdblack, blue, green, red, and white
The power curve in the Sword and Shield era was getting so intense that if The Pokmon Company introduced a card more powerful than the mighty VSTAR, it would probably need to have 500HP and award four prize cards in order to be balanced
I dont think Wizards ever made a statement about how many cards can fit in these boxes
