If you are signed up to Youtube -check your channel. Channel > Video Manager > Create > Audio Library The next tab is sound effects and there's thousands. Just use the search tab to find one you are looking for and you can also download it in a click!
That music is for Youtube videos, they are free to use, but I do not know if they can be used in Videogames.
I didnt say it was the music - the sound effects can all be downloaded - there's even a download icon for each file.