123RF $ – royalty-free photos, vectors, footage, and audio
BigStock $
CutStockFootage
Eezy – Vecteezy, Brusheezy, and Videezy
FreeStocks https://freestocks.org/
Free Stock Music https://www.free-stock-music.com/
GraphicRiver (Envato Market) $
MediaLoot – graphic design resources
Negative Space https://negativespace.co/
New Old Stock https://nos.twnsnd.co/ – vintage photos from publicl archives
New York Public Library https://digitalcollections.nypl.org/
StockSnap.io https://stocksnap.io/
The Stocks http://thestocks.im/ – search other stock sites
Videvo https://www.videvo.net/
Wiximedia Commons https://commons.wikimedia.org/wiki/Main_Page