One little thing I found helpful when searching for music that could legally be used in videos was looking on Soundcloud, searching for a track, then on the bottom-left-hand side under "filter results" you select the "to share" option rather than "to listen to."
This will pull up songs that are all under a Creative Commons License, and by clicking on the actual creative commons license logo/link in the song description it tells you the rules for using that song (usually it's just something along the lines of "give the artist credit").
Here is a link to the PWNAGE #2451 2016 reveal video:
https://www.youtube.com/watch?v=Vz802bi4MEo