Which champions have become more popular recently in League of Legends and why?

In most cases, a champion's popularity depends on their meta status, and if they are heavily nerfed, playing them is not very enjoyable. For this reason, we can track the rise in popularity of champions like Lee Sin, who recently received a nice buff.
There is, however, one exception: the already popular Ahri became even more popular after Riot Games released a set with an exclusive skin in honor of Faker's induction into the Hall of Legends. You can watch the event and set trailer here: https://www.youtube.com/watch?v=hRM0yZvVn2E