Hello there Jammers!
I just set up a 60% OFF Sale for all my audio assets on Itchio, and wanted to share it with you: https://itch.io/s/28578/quarantine-jam-sale
In addition to that, I also have some short 8-bit music loops collected in my personal website, they're free to use and released under CC Attribution license: https://www.filippovicarelli.com/8bit-game-background-music.html
For even more music, check out my website PlayOnLoop.com, there are plenty of short music loops that can be used for free under CC Attribution license (just browse the website and look for the yellow button "Free Download").
Happy creating! :D