Music on Vine - Vine, now with music. Make 6-second music videos.
Abundant Music - Generate royalty free music with a simple but very powerful procedural music creator
Lomotif - Instantly create and share awesome music videos
AIVA - The AI composing emotional soundtrack music
Typito - Web based drag-and-drop tool to create engaging videos with beautiful typography, images and brand layouts.
WolframTones - Listen to what I just found in the WolframTones music universe