A 3/3/1 character who can challenge, quest, or sing a 3-cost song on turn two is very hard to respond to

Madison Li 1 Rex, Cyber-Hound 1 Liberty Prime, Recharged 1 Nick Valentine, Private Eye 1 Elder Owyn Lyons 1 Curie, Emergent Intelligence 1 James, Wandering Dad 1 Shaun, Father of Synths 1 Synth Infiltrator 1 Sentinel Sarah Lyons 1 The Motherlode, Excavator 1 Red Death, Shipwrecker 1 Brotherhood Scribe 1 Paladin Danse, Steel Maverick 1 Sentry Bot 1 Robobrain War Mind 1 Assaultron Dominator 1 Synth Eradicator 1 Arcade Gannon 1 Behemoth of Vault 0 Lands (37) 4 Plains 4 Mountain 5 Island 1 Skycloud Expanse 1 Terramorphic Expanse 1 Exotic Orchard 1 Glacial Fortress 1 Evolving Wilds 1 Command Tower 1 Buried Ruin 1 Sulfur Falls 1 Clifftop Retreat 1 Temple of Enlightenment 1 Temple of Epiphany 1 Mystic Monastery 1 Myriad Landscape 1 Prairie Stream 1 Ash Barrens 1 Spire of Industry 1 Irrigated Farmland 1 Path of Ancestry 1 Razortide Bridge 1 Silverbluff Bridge 1 Rustvale Bridge 1 Treasure Vault 1 Ferrous Lake 1 HELIOS One Spells (39) 1 Swords to Plowshares 1 Sol Ring 1 Thirst for Knowledge 1 Lightning Greaves 1 Wayfarer's Bauble 1 Talisman of Progress 1 Mind Stone 1 Austere Command 1 Open the Vaults 1 Everflowing Chalice 1 Dispatch 1 Thought Vessel 1 Panharmonicon 1 Glimmer of Genius 1 Mechanized Production 1 One with the Machine 1 Crush Contraband 1 Talisman of Conviction 1 Talisman of Creativity 1 Mystic Forge 1 Arcane Signet 1 Wake the Past 1 Unexpected Windfall 1 Overencumbered 1 Intelligence Bobblehead 1 Nuka-Cola Vending Machine 1 Vault 112: Sadistic Simulation 1 T-45 Power Armor 1 C.A.M.P

Absolutely priceless.
Breakout cards in tournaments that shake up the meta can also cause cards that arent even on this list to rise up if players want to make their decks look extra shiny for big tournaments
For example, if you resolve Invoke the Ancients while you control Parallel Lives, you will choose a type of counter for each of the four resulting tokens
HIDETSUGU AND KAIRI The most cool-headed and practical of all the spirit dragons, Kairi knew that if Kamigawa were to survive, it would need all the help it could get, even if that help came from less-than-desirable sources Hidetsugu was surprised to find that his jailbreaker was none other than the reincarnation of the dragon he had slain