Harmony has a built-in script editor using JS (ECMAScript). Scripts can:
Typical use: Rename all layers in a scene, export selected drawings to PNG sequences with specific naming. Toon Boom Harmony Plugins
If you are looking to improve your workflow, you generally don't download single plugins; you download packages. These are the industry standards. Harmony has a built-in script editor using JS (ECMAScript)
Harmony comes with a "Vault" of pre-installed scripts that are not enabled by default. Typical use: Rename all layers in a scene,
The ecosystem is community-driven. The best places to hunt for new tools are: