https://aescripts.com/auto-crop/
Auto Crop allows you to instantly crop a composition down to the size of its contents. Crop a composition at the current frame or analyze an entire composition’s content and crop without cutting off any animation. Auto Crop 3 now even allows you to crop the current comp without it needing to be a pre-comp. In the newest version, Auto Crop has been rebuilt from the ground up as a native plug-in to provide new features and better results.