What if you don't have any music that will work in your project? Make your own. Below are a list of tools for creating your own music.
AudioSauna - Use synthesizers and effects to create your own songs, use your keyboard as the instrument
- No sign up needed
UJAM - Another music tool that let you record and tweak your own songs
Beat Lab - Create music using a grid
audiotool - Combine together the devices you want to create your music
Incredibox - Fun music game, but you have to purchase each song you make
LMMS - Open source music creation software