Spotify is one of the leading websites for musical selections. You can find artists, even those considered obscure, within their vast databanks.
You can find great videos that feature meditation music. Some go on for hours with deep, relaxing melodies that are good for sleep.
TunePocket.com is a multi-genre library with thousands of music tracks, loops, and sound effects. They can be mashed together and compiled to create an excellent meditation soundtrack.
The website is full of already crafted songs that can give you the atmosphere you intend. The music will continuously play as a radio-based website with little to no commercial breaks to disrupt your meditative state.