This deck does not appear to be legal in Standard (Season from Sep 2021).
Problems: You cannot play more than 4 of: Aether Gust, Beanstalk Giant // Fertile Footsteps, Bonecrusher Giant // Stomp, Brazen Borrower // Petty Theft, Brineborn Cutthroat, Casualties of War, Cauldron Familiar, Cavalier of Flame, Cavalier of Gales, Cavalier of Thorns, Chemister's Insight, Deafening Clarion, Devout Decree, Disenchant, Duress, Edgewall Innkeeper, Epic Downfall, Fires of Invention, Flame Sweep, Foulmire Knight // Profane Insight, Frilled Mystic, Gadwick, the Wizened, Gilded Goose, Growth Spiral, Hydroid Krasis, Kenrith, the Returned King, Korvold, Fae-Cursed King, Lava Coil, Leafkin Druid, Legion Warboss, Lovestruck Beast // Heart's Desire, Lucky Clover, Massacre Girl, Mayhem Devil, Midnight Reaper, Murderous Rider // Swift End, Mystical Dispute, Negate, Nightpack Ambusher, Nissa, Who Shakes the World, Noxious Grasp, Opt, Order of Midnight // Alter Fate, Paradise Druid, Quench, Questing Beast, Return to Nature, Risen Reef, Shifting Ceratops, Shimmer of Possibility, Sinister Sabotage, Sorcerous Spyglass, Sphinx of Foresight, Teferi, Time Raveler, Thrashing Brontodon, Trail of Crumbs, Vraska, Golgari Queen, Wicked Wolf, Witch's Oven. · Not legal in this format: Absorb, Aether Gust, Agent of Treachery, Angrath's Rampage, Arboreal Grazer, Beanstalk Giant // Fertile Footsteps, Bonecrusher Giant // Stomp, Brazen Borrower // Petty Theft, Brineborn Cutthroat, Casualties of War, Cauldron Familiar, Cavalier of Flame, Cavalier of Gales, Cavalier of Night, Cavalier of Thorns, Chemister's Insight, Cindervines, Claim the Firstborn, Deafening Clarion, Deathless Knight, Devout Decree, Dovin's Veto, Drill Bit, Edgewall Innkeeper, Embercleave, Embereth Shieldbreaker // Battle Display, Epic Downfall, Escape to the Wilds, Expansion // Explosion, Fae of Wishes // Granted, Fervent Champion, Finale of Devastation, Fires of Invention, Flame Sweep, Foulmire Knight // Profane Insight, Frilled Mystic, Gadwick, the Wizened, Giant Killer // Chop Down, Gilded Goose, Golos, Tireless Pilgrim, Growth Spiral, Gutterbones, Hydroid Krasis, Ionize, Justice Strike, Kenrith, the Returned King, Knight of the Ebon Legion, Korvold, Fae-Cursed King, Lava Coil, Leafkin Druid, Legion Warboss, Legion's End, Lovestruck Beast // Heart's Desire, Lucky Clover, Massacre Girl, Mayhem Devil, Midnight Reaper, Murderous Rider // Swift End, Mystical Dispute, Nightpack Ambusher, Nissa, Who Shakes the World, Noxious Grasp, Opt, Order of Midnight // Alter Fate, Paradise Druid, Planar Cleansing, Priest of Forgotten Gods, Quasiduplicate, Quench, Questing Beast, Ral's Outburst, Rankle, Master of Pranks, Rimrock Knight // Boulder Rush, Risen Reef, Ritual of Soot, Rotting Regisaur, Scorching Dragonfire, Shifting Ceratops, Shimmer of Possibility, Sinister Sabotage, Skarrgan Hellkite, Smitten Swordmaster // Curry Favor, Sphinx of Foresight, Teferi, Time Raveler, The Great Henge, Time Wipe, Tithe Taker, Trail of Crumbs, Vivien, Arkbow Ranger, Vraska, Golgari Queen, Wicked Wolf, Witch's Oven.