An incredibly interesting collection of cards is the nine variations of Nazgl to represent the nine men who became them
As a permanent is phased out, Auras and Equipment attached to it also phase out at the same time
Its ability looks pretty insignificant at first but combined with certain cards, it can help you produce infinite mana, buff your creatures with a gazillion counters and draw at the same time, or even have infinite turns
WotC internally calls it the Thalia problem, so with this example, you might have two of the Dark Ascension art, one of the Innistrad: Crimson Vow , and if you wanted the Multiverse Legends one, you'd only need to craft one new rare wildcard to allow four of that style to grace your decks
Harmonious Emergence's replacement effect does not replace effects or costs that require you to sacrifice the enchanted land