Software

If you have a plugin that is just a .aex file, it must be installed manually. To do this, simply copy the .aex file into the After Effects Plug-ins folder.

Dance Effect provides an easy method to animate your videos to a music track.

LayerRender Free allows the user to render 8-bit H.264 at the layer level using an external FFmpeg installation.

A list of free plugins on this site.