why isnt there a custom list of champion to choose from?

Like in champion select.

Just now I was deciding who's best against pantheon. Right when I figured mao was my best choice I kept MISPELLING mao. I have a lot of champions unlocked so it would have taken me forever to scroll through the list to find him. So then I ran out of time and boom.. 6 minutes and a;ldkfja;sldfj;alsd;k

ffs this was suggested ages ago and I dont see why this can't be added.