In Commander, its very much possible to stack up multiple emblems by replaying Sephiroth from the command zone, and once youre at that point, the games probably over
Changelings are interesting because treefolk are usually expensive, so cards like Masked Vandal and Chameleon Colossus lower the curve and add versatility
You can double its effects with creature entering effect doublers
Open the Kit and the decks, click the decklist in Collection, and jump into a casual game quickly
Depending on your deck, you might also want to look at Clever Concealment, Flawless Maneuver and Cosmic Intervention the latter of which is a lot of fun with fetchlands and mass land destruction, or board wipes when you run a lot of strong EtB effects