#19: Near-Death Experience A similar path to that traveled with Barren Glory exists here for Boros mages, incorporating Worldfire or Soulgorger Orgg to decimate yourself in the name of one big Near-Death Experience turn

Abrupt Decay Active Volcano Aegis Angel Ajani Vengeant Alpha Deathclaw Angel of Despair Angelic Rocket Argentum Armor Argentum Masticore Ass Whuppin' Assassin's Trophy Atomize Avalanche Riders Awaken the Honored Dead Awaken the Maelstrom Ayli, Eternal Pilgrim Bahamut, Warden of Light Bane of Progress Beast Within Behemoth of Vault 0 Binding the Old Gods Black Bolt, Inhuman King Bladegriff Prototype Blast Zone Blue Elemental Blast Bone Shredder Bounty Agent Bramblecrush Break the Spell Brink of Disaster Bronze Tablet Bumbleflower's Sharepot Capricious Efreet Captain's Hook Cavalier of Dawn Chain of Acid Chaos Confetti Chaos Defiler Cityscape Leveler Clay Golem Cloudchaser Kestrel Combustion Man Commander Sofia Daguerre Corrosion Cramped Bunker Crosis's Charm Culling Ritual Culling Scales Dark Temper Deadeye Harpooner Death Begets Life Decommission Deep-Fried Plague Myr Defiant Vanguard Desert Twister Despotic Scepter Destructor Dragon Detention Vortex Display of Dominance Drag to the Roots Druid of Purification Emerald Charm Emergency Eject Engineered Explosives Excavation Technique Extinguisher Battleship Eye of Doom Eye of Singularity Fatal Push Fate of the Sun-Cryst

Finally, when you spend five energy you get to return an artifact from your graveyard to the battlefield
Saheeli, the Suns Brilliance Saheeli, the Sun's Brilliance underwhelmed me at first, but after further consideration, Im impressed
Each Class permanent tracks its own level separately