Google Translate says it's LOL Tanabata 104 heroes blessing so there must be every single Champion released so far in this picture. Tagged all I could see at first.
K Added the names of everyone. Not sure 100% if those are the correct skins for vlad and ashe and dont have a single idea whats with Cho having ponytails. :I
GeeTeeEye said: That's Leona, not Zyra. Look at the little diamond-shaped hair ornaments.
A bit late on this, but the girl hugging Maokai isn't Leona because Leona is kissing Pantheon in the top-center of the image. It's Zyra in a completely different costume, mostly likely.