While we may get Llanowar Elves, Elvish Archdruid, Dwynen's Elite, and Lathril, Blade of the Elves in Foundations , I don't think those cards can realistically beat a Day of Judgment deck
Quantum Riddler Quantum Riddler has two main modes: the warp mode, where it enters the battlefield and cantrips, and the 5-mana mode, where its a big 4/6 flier, like Consecrated Sphinx, that immediately draws you another card
You can win via Infinite Combos , One-Shot Commander Damage , or Mass Drain (Gollum/Sanguine)
Keruga, the Macrosage actually benefit from some split cards since its a way to cheat on the companion requirement while still having cheap spells to cast
2 + 4 + 4 is easy, whereas 1 + 4 + 4 needs a Noble Hierarch, Pendelhaven, or stray infect tap for one to get there
After 16 years, the card was reprinted in 2011 as a DCI Judge Promo, but the card would of course still remain incredibly rare and hard to come by