F-list is my go to for roleplay because it's easy to get your roleplay idea out there and seen by multiple people. Just hop into one of their many chatrooms and post your ad and if people are interested they can message you and you can start chatting!
It takes a lot of patience to wait for someone to bite, but I believe that it's the best site for erp, anthro or human plus you get to make a character profile and list of all your likes and dislikes so people know what you're into.
I've used Chatzy for convenient 1-on-1 roleplays when the rp by mail technique on here gets annoying. It's sort of similar to f-list in that some chatrooms will allow you to post your ad in chat, but the private messaging system is pretty barebones and works more like an old AOL mail system rather than an IM chat.
However, I think Discord has slowly become the preferred place to roleplay for many people because it's easy to keep all your friends in one place and post images in chat, but for some reason it hasn't grown on me.
Kik is another strange one to me. Doesn't it delete your past conversations after you've logged off for privacy reasons? Bit of a hassle to have to remember to save all your conversations before logging out.