Not so fine print (license stuff)
You can use these videos and gifs however you like (except sell them). Edit the videos into your own YouTube videos. Post the gifs wherever kids post gifs these days. I like Giphy's gif processing, but they end up pretty chunky. You might have better luck compressing the gif yourself (the source is the linked mp4 file).
I use royalty-free music, but I have no control over YouTube's ContentID system. If you're concerned about copyright strikes, I'd recommend blanking out the audio and pulling from YouTube's music library.
You can request additional drops using the regular IntroCave Request Video form, but keep in mind the parameters: is this something anyone could use?