New Champs

Hello everyone, I have been playing League for about 2 years now and I want to invest more time into one champion, so I can become good at this champion or a one trick pony at this champion. I don't really know which champion to start with and right now I really enjoy playing champions like Nami , Janna , Lulu , Caitlyn , Karma , and I've lately benn playing Katarina and Irelia . Katarina and Irelia are alright for me, but don't really fit my playstyle. Even though I really enjoy playing those champions, I want to start mastering a new champion. Can you recommend me any champions please? Thanks