The official mootools.net site has finally opened a plugin library for the Mootools framework. You can find it at http://mootools.net/forge/
Each plugin in the library has detailed information presented in a very convenient format:
- Release version history
- Author information and contact
- Full documentation
- Live examples and demos
Hopefully this library will grow as actively as the jQuery plugin repository at http://plugins.jquery.com/ — where you can always find something useful.
P.S. It would be even better if they added examples for each of the framework's built-in methods...