HelloTalk Free app (Android and iOS) for finding conversation partners around the world and at home. More info is here.
Italki ("I talk-y") Find conversation partners and paid tutors. More info is here.
Speaky Find partners, chat or make audio/video calls in your browser. Currently (2017) only allows you to sign up via Facebook or Google.
The Mixxer Find language partners and talk to them via Skype.
Verbling Designed to help you find native-speaking tutors, and video-chat with them on the site via your browser.
Nesuku Recent start-up. Connect with native speaker conversation coaches or teachers for $10/hour. The conversation coaches and teachers are vetted by the site, so if you can afford the fee, you can work consistently with the same native speaking conversation coach. The site attempts to partner you with conversation coaches whose profile/interests are a good match for you.