Samsung Gear Lite - Just through test flight.
You sign up on the Samsung web page. Its in Korean, but US users can do it too, as the app itself is multi-language. They ask a few simple questions, which you can use google translate to view and you can answer in English. Apple sends you a link with a code and you enter that code into the test flight app and the Samsung app will then appear for you to install.
But as I write this, I think the beta sign up appears to be over

But you can try the link yourself, if interested:
https://ko.surveymonkey.com/r/LWCPBRQ