Please embed your YouTube samples in this forum using the tools ta the top of the reply bar and give us a clue which part of the video you want to figure out by giving us a time. You could also take a screenshot of the video and just drag it to the reply field in this forum: Putting a link in the title of a page is almost useless. It's nearly impossible to copy or follow.
That said if you mean something like this part of the video:
Then that's not a plug-in or effect, it's animation.
It would also be very helpful to know what your skill level is and what your illustrator art looks like. Flowing animation could mean anything.
BTW, according to the comments the "effects pack" represented here is a bunch of stolen work from other AE artists. I'd be wary about buying anything from the creator of the video.