Harmonize [cost] means You may cast this card from your graveyard by paying [cost] and tapping up to one untapped creature you control rather than paying this spells mana cost, If you cast this spell using its harmonize ability, its total cost is reduced by an amount of generic mana equal to the tapped creatures power, and If the harmonize cost was paid, exile this card instead of putting it anywhere else any time it would leave the stack. Casting a spell using its harmonize ability follows the rules for paying alternative costs in rules 601.2b and 601.2fh
Jecht, Reluctant Guardian A 4/3 for four with menace is pretty average, but thankfully, the backside of Jecht is the side that really pops
This deck draws a lot of cards
Choosing to play all five colors and having all the best cards in Magic available at your fingertips, only to choose to run Dromoka, the Eternal is hilarious
Rounding things out, Id recommend Serah Farron as a great cost reducer in your Legendary-matters decks
The name of the game for these commanders is to control the board, benefit from graveyard synergies, and slowly dwindle your opponents decks
