ProtonGraph
A free and open source node-based software for procedural content generation.

Node-based
- Each single node only does one thing.
- Connect them together to create complex results.
- Free and Open source (MIT) makes it easy to add your own nodes.

Procedural generation
- Your node graph is a rule set.
- It's deterministic.
- What you create is up to you.

Clutter-Free interface
- It's all empty when you start a new project.
- Most of the UI is contained within each nodes.
- You're the one placing the nodes so you're in total control on how the UI evolves.
And more
You can find out all the details on the Github project page.