What theme / template can I use with 1-Click Video Site Builder?
The plugin should work with pretty much any theme, including your favorite one.
That said, here are a few themes to get you started:
http://www.fabthemes.com/garvan/
https://colorlib.com/wp/themes/pinbin/
https://wordpress.org/themes/novavideo-lite/
https://wordpress.org/themes/travelify/
:-)