See gdx-lml.
This is an example project using LML templates to create GUI. Java part of the code explores some of the more advanced gdx-lml functionalities, like creating custom tags, macros and attributes. Example templates include usage of pretty much every tag and macro available in gdx-lml by default.
Check it out on-line (be careful through: on-line version might be slightly outdated or use latest snapshot with new features).
It uses a simple, custom UI skin defined at assets/skin.json. The design is (somewhat) based on the great VisUI library, but obviously not as complex or polished. It has pre-defined styles for all default Scene2D actors, so it can be useful for quick prototyping - if you want to use these assets in your project, feel free to do so. You can modify raw skin assets at core/raw and run gradle pack task to recreate the atlas file with your changes.
