Sounds and Music
- Kevin MacLeod – Hundreds of music tracks in a wide range of genres (CC-BY)
- Freesound – Lots of creative commons sound effects and music.
- OpenGameArt.com – Art, music, and models. Under a vareity of licenses, so pay attention.
- Green Island soundtrack by Alpha Secret Base
Images and artwork
- CC Search – Search several media and image sites for creative commons content.
- OpenGameArt.com – Art, music, and models. Under a vareity of licenses, so pay attention.
Fonts
- Font Squirrel – Lots of awesome fonts with a free commercial licenses.
Random stuff
- Alpha Secret Base (Japanese only) – Games, music, art, etc… The content is under a BSD license according to this notice unless a more specific license is included on a page / in a file.