(please note: you also need to check the sites regulations and license rules - they differ from site to site)
https://www.jamendo.com (not always free)
https://www.audioagency.de (not free)
Also check the editing software you're using options!
wevideo: https://www.wevideo.com (some participating universities have pro licenses like PHOÖ and Aberdeen - contact coordinators if you want to use them)
Youtube Editor (very limited options):
iOS and Android:
https://luma-touch.com (also multitrack video editing)
https://itunes.apple.com/at/app/imovie (only single track video editing)
Computers all operation systems (free):
Mac OS X:
OS X and Windows:
Windows Movie maker
Link to Video MOOK: https://www.oncampus.de/weiterbildung/moocs/videomooc
Link to Tutorial about camerawork (a little bit old, but still useful): https://vimeo.com/128855961 (The password is: phtvcamera)
More coming ….!