Heres the list I came up with, and then Ill mention certain relevant cards
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
The Haunt of Hightower The Haunt of Hightower exploits discard as a source of counters to become a Voltron commander
Load your deck full of Defiant Strike and Shelter style effects and Feather will make sure your hand is never empty
The rainbow foils had a bit of a thick, plasticky coating on them, which wasn't my favorite