Ask yourself what you enjoy most in league.
What role, if any, is the most fun and satisfying for you?
If you cannot think of any then are you even having fun playing the game anymore?
If you can think of any then that will help you narrow down your options.
If there is a role you enjoy more than any other, what is it about the role that you enjoy doing?
If you can answer that question then ask yourself what champion in your preferred role best accomplishes what it is that you enjoy most about that role.
If you do not have a preferred role and if you feel you are no longer having fun playing the game then it might be time for you to stop playing league for a while.