There are many excellent plugins for After Effects, and which ones are the best for you will depend on your specific needs and workflow. I'm sharing my favorite Adobe After effects plugins that help me to speedup my motion design, video editing workflow and adding new features.
01 - Overlord
Transfer shapes between Illustrator and After Effects in a single click.
Work with shapes, not files.
Download Overlord
02 - After Codecs
Giving you the best and missing codecs for faster exports!
H264 and ProRes422.
( UPDATES: Ae 2023 version has H.264)
Download AfterCodecs
03 - Motion 2
Motion is brilliant. It features 20 really powerful tools. Easy ease, Anchor point is my fav
Download Motion 3
04 - Limber
Animating 2D characters quicker and easier. Path to bone, IK FK, Anti pop
Download Limber
05 - GifGun
Lets you export gifs from animations or video in a single click Alpha channel, Compression
Download GifGun
06 - Joysticks 'n Sliders
Pose-based rigging system commonly used in 3D character rigging Move to Parent/Child comp, Ease Bias
Download Joysticks 'n Sliders
07 - Cloners+Effectors
Procedural animation system for After Effects. Especially useful when animating multiple layers at the same time.
Download Cloners+Effectors
It's worth noting that these are just a few examples, and there are many other great plugins available for After Effects. It's always a good idea to try out a few different options to see which ones work best for your specific needs.