Mixkit
Mixkit focuses on music, sound effects, and video assets.
What it does
Mixkit collects video assets, music, and sound effects in one place.
When to use it
For a short video, test whether music and transition effects overpower narration.
Visit Mixkit official site
Bensound
Bensound focuses on music browsed by mood and intended use.
ccMixter
ccMixter focuses on audio material and tracks for remixing.
Epidemic Sound
Epidemic Sound focuses on music for videos, streams, and shows.