Oh neat I finally found this magic list after ... ... Mr. Male Rooster gave me the hints there.
That top tab that says THE GAME has a drop down. Hover over "Game modes." That'll open a side menu drop down. Hover over ELO. That'll create yet another side drop list of links. One of them is "Banned characters." Click that.
Now, I BELIEVE from there that what you see before you is what is in effect at this very moment/week. If you click next, you can see what the next week is going to be.