Looking For help in Choosing Secondary Champions

Hello everyone, this is my second ever post so please be kind. I have been playing quite a bit of Rengar lately and am considering maining him. The only problem is, I don't really have any secondary champions I like to play for jungle and/or mid(I'm not playing Rengar mid just to clarify). I was wondering if some of you guys could help me out and recommend some champions for me to try that are similar to Rengar for any lane really. I would appreciate any written out posts or any responses to the poll I am attaching. Thank you all in advance for your feedback and for taking time out of your day to help me.