Advanced Mask Editor 2 from Nataworkstudio is an After Effects tool for expanded mask editing. It provides a panel that shows all the mask sets on a selected layer, rather than twirling down menus to reach them.
Beyond the standard After Effects masking tools, it can merge mask paths together, mirror them, replicate them, and open or close paths. This release also works with animated masks: you can merge two animated masks into one, and copy, flip, or mirror an animated element. A set of 60 animated presets is included.
The current version is 4.1.02, last updated on January 7, 2025. Advanced Mask Editor 2 supports a wide range of releases, from After Effects 2025 back through the CC versions to CS6, CS5.5, and CS5. A demo video is available.