I honestly recommend checking out WotC's Secret Lair Heads I Win, Tails You Lose deck
It can be played for only the cost of four ink via its Shift 4 keyword ability, and it also has the helpful Evasive keyword ability

1 Bello, Bard of the Brambles [7M5v0rCo4IuTICf7OMwnCj] 1 Wildsear, Scouring Maw 1 Domri, Anarch of Bolas 1 Etali, Primal Storm 1 Prosperous Bandit 1 Pyreswipe Hawk 1 Alchemist's Talent 1 Berserkers' Onslaught 1 Outpost Siege 1 Rain of Riches 1 Chaos Warp 1 Sunbird's Invocation 1 Gratuitous Violence 1 Warstorm Surge 1 Starstorm 1 Lotus Cobra 1 Evercoat Ursine 1 Brightcap Badger 1 Trailtracker Scout 1 Thickest in the Thicket 1 Ghalta, Primal Hunger 1 Esika's Chariot 1 Unnatural Growth 1 Greater Good 1 Kodama of the East Tree 1 Grothama, All-Devouring 1 Rampaging Baloths 1 Bootleggers' Stash 1 Primeval Bounty 1 Gilded Lotus 1 Spine of Ish Sah 1 Temple of Abandon 1 Karplusan Forest 1 Exotic Orchard 1 Sheltered Thicket 1 Game Trail 1 Raging Ravine 1 Copperline Gorge 1 Mossfire Valley 1 Cinder Glade 1 Rootbound Crag 1 Mosswort Bridge 1 Blasphemous Act 1 Llanowar Loamspeaker 1 Tendershoot Dryad 1 Goreclaw, Terror of Qal Sisma 1 Path of Discovery 1 Decimate 1 Rolling Hamsphere 1 Teapot Slinger 1 Explore 1 Farseek 1 Cultivate 1 Grumgully, the Generous 1 Wandertale Mentor 1 Thought Vessel 1 Arcane Signet 1 Wooded Ridgeline 1 Big Score 1 Abrade 1 Rampant Growth 1 Sakura-Tribe Elder 1 Beast Within 1 Garruk's Packleader 1 Harmonize 1 Garruk's Uprising 1 Gruul Signet 1 Burnished Hart 1 Hedron Archive 1 Fellwar Stone 1 Thran Dynamo 1 Sol Ring 1 Mind Stone 1 Talisman of Impulse 1 Terramorphic Expanse 1 Path of Ancestry 1 Gruul Turf 1 Evolving Wilds 1 Forgotten Cave 1 Tranquil Thicket 1 Command Tower 1 Reliquary Tower 8 Mountain 10 Forest Animated Army Tokens 1 Treasure // Beast (3/3) token 1 Treasure // Prosperous Bandit Offspring token 3 Treasure // Saproling tokens 1 Hamster // Saproling token 2 Cat // Beast (4/4) tokens 1 Hamster // Beast (3/3) token 1 Hamster // City's Blessing token See the tokens from Animated Army in the Bloomburrow Card Image Gallery

This means you could put this mana into something like Urza's Ruinous Blast or Karn's Temporal Sundering at a pivotal moment
Similar to trading card games such as Magic: The Gathering and Pokmon, Disney Lorcana allows two players to create a custom deck of cards before battling their decks to see who emerges the winner
Theres no time to change what the creatures are attacking or which creatures are attacking since you return a creature as part of the ninjutsu cost after blockers have been declared