The first turn you play it, unless you are in dire need of cards, you should probably use its +1 ability to bring its loyalty up to 4
Generally, red card advantage concerns EDH more than other formats, so this list will be geared towards getting value there
The type-changing effect of the reflexive triggered ability lasts indefinitely
Emet-Selch is right in that sweet spot when it comes to eternal playability in Magic: The Gathering
Arclight Phoenix When people see Arclight Phoenix, some might think: Hey, its cute when it goes off, in Magical Christmas Land. In reality, its way easier to bin and bring back multiple Arclight Phoenix in a turn: You just need some cantrips and cards that draw and discard, like Faithless Looting or Chart a Course
But dont forget the more flexible cards, like Thraben Charm