Scripts

KdenParse [1]: A python script to convert your Kdenlive project file to an EDL playlist, script created by a Kdenlive user.
See forum post [2].

Background textures

A list of free images : http://aefreemart.com/2009/08/27/how-to-get-the-best-free-images-in-the-... [3]

Keyboard stickers

Inkscape SVG & Printable PNG: compressed svg & png files [4]
(For more infos, see forum post by Weevil [5])

Music

Creative Commons [6]
Music for Video [7]
Vimeo Music Store (Creative Commons in addition to commercial) [8]

Links:
[1] https://github.com/barry-lyndon/KdenParse
[2] http://kdenlive.org/forum/announcing-kdenparse-python-kdenlive-project-file-parser-generates-edl-sort-and-other-stuff
[3] http://aefreemart.com/2009/08/27/how-to-get-the-best-free-images-in-the-internet/
[4] http://kdenlive.org/images/keys.tar
[5] http://kdenlive.org/forum/keyboard-stickers
[6] http://creativecommons.org/legalmusicforvideos
[7] http://music-for-video.com/
[8] http://vimeo.com/musicstore
[9] http://http://www.friendlymusic.com/