Note that, because thats playing the full twenty fetchlands, unless you want Evolving Wilds, your mana gets worse after that, so its hard to justify even considering going over 80 cards in Standard, but I can imagine a reasonable case for anywhere between 60 and 80 moving forward, especially thanks to Ben Rubins proof of concept

$54.99 Teferi, Hero of Dominaria Masterpiece Series: Mythic Edition $0.79 Bone Shards (Retro Frame) Modern Horizons 2 Variants $9.49 Gideon of the Trials (SDCC 2017 Promo Foil) Promotional $2.99 Talisman of Curiosity (Foil Retro Frame) Modern Horizons - Retro Frames $22.99 Fanatical Devotion Nemesis $6.99 Ashiok, Nightmare Muse (Borderless) Theros Beyond Death Variants $84.99 Chandra, Torch of Defiance (SDCC 2018 Promo Foil) Promotional $12.99 Impulsive Maneuvers Odyssey $27.99 Oko, Thief of Crowns (Borderless) Throne of Eldraine Variants $4.49 Priest of Forgotten Gods Ravnica Allegiance $24.99 Viscera Seer (Extended Art) Commander Legends Variants $15.99 Smokestack Urza's Saga 0 results found
And it is typically based on changes in the game's balance or mechanics
Each winner received 100 copies of an unnumbered promo card featuring their illustration in their native language
Suddenly youre in a race, one side questing for 1, another questing for 2, and Maleficent just wins that race outright, even though Minnie was down first and starts questing first
[23] Use the sold filter for eBay results to see what people actually paid for singles if youre seeing all kinds of whacky prices