First let me get the other skins out of the way and if you stick around till the end, you can get my Legendary skin idea reveal ;D
Pool Party Evelyn. That's a given.
Virus Evelyn. The anti-program skin
Runewar Evelyn. Evelyn from the beginning when she first came into existence
Coven Evelyn. Just. Muah. Perfect.
Demon Queen Evelyn- In a version of Runeterra, the near future, Evelyn has succeeded in starting a new Runewar, pitting Noxus and Demacia into a full fledged conflict that subsequently drew in the other Runeterran nations. She always asked herself, "Who does a girl have to kill to start another Runewar?" and the answer was Ryze. Only he could stop her reign of Terror and the mage must make an uneasy alliance with unlikely friends like Tahm Kench, who absolutely hates the fact that Evelyn is running roughshod over his territory, in order to stop her. The fear and despair has given Evelyn unspeakable power and its up to Ryze to take back the runes that Evelyn released into the world before Evelyn finds him, and kills him for good.