The Haunt of Hightower The Haunt of Hightower exploits discard as a source of counters to become a Voltron commander
Key Cards Terra, Magical Adept // Esper Terra Terra, Magical Adept can get you a summon from the top five cards of your library while the rest get milled
Scion of Draco also fits multicolor decks pretty well, being able to give plenty of combat-related bonuses to gold creatures, and surprise, surprise, Leyline of the Guildpact also helps with these bonuses, extending them to all creatures including the Scion itself
Rounding out the list are some noncreature spells with strong Legends synergy, mostly ramp like Leyline Immersion and Relic of Legends but also other stuff like board wipe with Urza's Ruinous Blast and mass reanimation with Primevals' Glorious Rebirth
Compared to White Sun's Zenith, you lose instant speed but create an extra token
Fix the common failure: Add lands, add draw, add answers, lower curve, add redundancy