Google Advanced Image Search (select free to use or share under usage rights)
NYPL Digital Gallery (Some of the images in the Digital Gallery may be subject to third party rights such as copyright and/or rights of privacy/publicity)
Artifact and Analysis (Smithsonian)
Europeana - Artwork, video and sound.
Everystockphoto - Search engine for free images.
Image*After - Database of images and textures.
Open Clip Art - Lots of free clip art.
Pics 4 Learning - Free copyright friendly images for educational use.
Splashbase.co - Images and video to freely use.
Stockvault - Over 60,000 images to browse and download.
Yale Digital Commons - Digital assets curated by Yale University.
ccMixter - Thousands of free sounds and music to download and use.
Piano Society - Classical piano music uploaded by users that is free to use.
YouTube Audio Library - Download background music for your video, completely free.
Jamendo - An independent music community with unlimited free streaming and downloading.
Free Music Archive - Many genres available as well as curated sounds to help you find what you need.
Melody Loops - Royalty free background music.
SoundBible - Free sound clips, sound bites and sound effects.
JamStudio - Create your own music online and download it. Registration required.
Opsound - Independent musicians with free music to use.
Audionautix by Jason Shaw - Original, electronic songs that are free to use.
Netlabels - Part of the Internet Archive. The collection is completely free with catalogs of virtual record labels.
Partners in Rhyme - Some pay and some free content. Also has effects, Midi and loops to use.
Moby Gratis - Created by the artist, Moby, Online application system, which registers you to use the site.
Incompetech - Background music to download by Kevin MacLeod.
Sound Search Engine - Huge site for finding sound effects.
Classic Cat - Find classical music for video soundtracks.
Purple Planet - Lots of free full length songs to download and use.
Zap Splat - Free sound effects with a huge variety to choose from.
PD Sounds - Public Domain sound library.
Cylinder Preservation and Digitization Project - Mostly Public Domain songs that have been digitized before 1924.
Soungle - Royalty free sound effect search engine.
Freesound.org - Samples and search engine with a forum for discussions.
CC Mixter - Search by genre, instrument and more with a variety of CC licenses.