SDL:
http://www.libsdl.de/logo/

GLFW:
n/a

SndFile:
n/a (http://www.mega-nerd.com/libsndfile/libsndfile.jpg perhaps?)

Chipmunk:
http://files.slembcke.net/chipmunk/logo/

OpenGL:
http://www.opengl.org/about/logos/

OpenAL:
http://connect.creativelabs.com/openal/Logos/Forms/AllItems.aspx

DevIL:
http://openil.sourceforge.net/logos.php

Freetype:
http://upload.wikimedia.org/wikipedia/commons/7/7e/FreeType-logo.png
