Clive, Ifrit's Dominant, Dion, Bahamut's Dominant and Jill, Shiva's Dominant start as Human Noble Warriors with reasonably impactful enter the battlefield triggers, but with the cost of their activated ability they transform into their powerful Saga Creature forms
If players can get "Moana, Kakamora Leader" into play, one of Azurite Sea's new cards, she can move any amount of characters in-play to the same location for free, and then gain +1 lore for each character
Ive used both Ghen and Arenson's Aura for political purposes in Commander games
A color that will do anything to get extreme power, and a crucial color in Constructed MTG formats right from the beginning of the game with its discard, removal, card draw, and impactful demons
You must ensure that your face-down spells and permanents can easily be differentiated from each other