Please help me decide which champion should I try next

So basically as the title says I assistance deciding which champion I should try next. My two favorite champions are and . 9 times out of 10 I will choose Cho. Whenever I do decide to try out a new champion they always seem to fall into the top lane category like or for example so what I really want would be someone who can fill another lane as I am in a real bind if someone manages to call top before me. I can mid with cho but that only gets me so far. The things that really drew me to gp and cho to begin with were their good sustain and the ability to stay in lane for a good amount of time. Please let me know if there are any champions that you would recommend for me to test out. Thank you to all that respond to this.