Here is the League of Legends Patch 10.19 mid lane tier list.
League of Legends Patch 10.19 Mid Lane Tier List
S Tier - Fizz, Yone, Kassadin, Yasuo
Yone has seemed to finally find his identity as a powerful mid laner. He has become the better brother and has ruled the mid lane as one of the highest banned champions in the game. Allowing Yone to gain momentum and win lane is dangerous as he can melt any back line picks like Caitlyn or Ashe. Additionally, the hitbox on Yone's ultimate ability, which is similar to Yasuo's, is much larger than players expect. Fighting team fights against a Yone whether it be for a mid lane tower or for an objective is something to be feared.
A Tier - Zed, Katarina, Sylas, Talon
Despite being one of the worst junglers in the game right now, Sylas is excelling as a mid laner. His sustain is the name of the game and when dueling champs during the laning phase or even late game, he becomes almost impossible to kill. While his ultimate ability, which steals enemy champ's ultimate abilities, is situational and only provides value based on matchups, he is still a viable pick.
B Tier - Ekko, Diana, Karthus, Annie
Similar to Sylas, Ekko is an excellent duelist. Ekko kit is based on angles and anticipation and has massive damage potential. While he can feel clunky in the early game, after an Ekko gets fed and wins the laning phase, it becomes difficult to kill him. His ultimate ability, Chronobreak deals massive burst damage, can act as a engage and is a great escape option. Adding Ekko to your rotation could provide massive benefits for your team at all points in the game, so consider adding him.