They are quite dominant in metagames
The list below includes the discard outlets I see most commonly played and used in drafting cubes
WHITE | BLUE | BLACK | RED | GREEN MULTICOLORED | SPELLBOOKS and CONJURE ALL CARDS WHITE Sandcloud Harbinger Cottontail Caretaker Three Tree Battalion Awestruck Cygnet BLUE Shellfish Scholar Pool Resources Tempest Trapper Archival Whorl BLACK Chittering Skullspeaker Tasteful Offering Putrefying Rotboar Sanguine Soothsayer RED Brave Meadowguard Cindercone Smite Charged Conjuration GREEN Vigorous Farming Fountainport Charmer Traverse Valley Bramblearmor Brawler MULTICOLORED Ace Flockbringer Dazzling Flameweaver Darkstar Banisher Thought Rattle Marshland Hordemaster Resourceful Collector Buxton, Decorated Host Indris, the Hydrostatic Surge Euru, Acorn Scrounger Recruit Instructor Leaf-Leap Guide Spellbooks and Conjure Charged Conjuration Empty the Warrens Galvanic Relay Grapeshot Dazzling Flameweaver Blade Juggler Body Count Dead Revels Drill Bit Hackrobat Light Up the Stage Rafter Demon Rix Maadi Reveler Skewer the Critics Spawn of Mayhem Spikewheel Acrobat Recruit Instructor Angelfire Ignition Barge In Become Brutes Boon of Safety Cheeky House-Mouse Crumb and Get It Defiant Strike Embercleave Feather of Flight Mabel's Mettle Might of the Meek Moment of Heroism Unleash Fury War Squeak Archival Whorl Rhystic Study Brave Meadowguard Might of the Meek Euru, Acorn Scrounger Chitterspitter Indris, the Hydrostatic Surge Lightning Bolt Sandcloud Harbinger Sunscorched Desert Sanguine Soothsayer Sanguine Bond Shellfish Scholar Think Twice WHITE | BLUE | BLACK | RED | GREEN MULTICOLORED | SPELLBOOKS and CONJURE ALL CARDS Pick up Alchemy: Bloomburrow packs in the MTG Arena Store beginning August 20!
The Core Set 2021 Bundle comes with ten Draft Boosters, and those boosters can contain showcase cards as well
There is a sub-theme of Aristocrats here because of how easy it is to make a Vampire
Quantum Riddler Quantum Riddler has two main modes: the warp mode, where it enters the battlefield and cantrips, and the 5-mana mode, where its a big 4/6 flier, like Consecrated Sphinx, that immediately draws you another card
