The image below shows a shadowless (left) and shadowed (right) card side-by-side
The most effective approach follows the traditional color pie that defines both identity and gameplay mechanics: White - The color of order and protection that focuses on efficient creatures, removal spells, and defensive strategies Blue - The color of knowledge and control that emphasizes card draw, counterspells, and manipulating the game state Black - The color of power and ambition that utilizes life as a resource, creature removal, and graveyard interactions Red - The color of freedom and emotion that delivers fast aggression, direct damage, and chaotic effects Green - The color of nature and growth that ramps mana, plays large creatures, and destroys artifacts and enchantments Colorless/Multicolor - Cards that either require no specific mana or combine multiple colors for hybrid strategies and flexible deck-building options This sets up a very simple organization system: color

Cards like Unruly Catapult, Galvanic Juggernaut, Traxos, Scourge of Kroog, Staff of Compleation, Bender's Waterskin, and the game changer, Mana Vault all have ways to untap themselves
Burning Abyss The Deceptive Matchup Take one look at the stats of the Burning Abyss archetype, yes, you will see they are low and that Jersey OTKs can happen
Megabot is your most useful one as a way to banish damaged characters, but having to banish it as part of the cost puts you down an Item in an already Item-sparse deck.