In the first video you could achieve that look using shape layers(which have a wiggle paths options) that will get you really close to this look. But this isn't a plugin you just drop over it, it's a time consuming process where you would draw on a shape, animate the path of that shape to mimic the video, then add the "wiggle paths" to the shape(perhaps adjusting the wiggle to your taste
The second video, if you are referring to the trumpets, looks like pretty much the same effect, cept they traced some clip art and then animated the shape layer.
Johnny Cuevas, Editor
"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.