Use Graph Toolkit to create node-based graph tools within the Unity Editor.

Graph Toolkit is a front-end framework to build custom graph tools with ready-made UI components and interaction patterns. Graph Toolkit includes extensibility features that you can use to customize implementations to meet your specific requirements. Graph Toolkit is best suited for developers who need to create specialized, graph-based tools that help designers, artists, and other team members to work independently without frequent programmer intervention. Although Graph Toolkit supports compilation to runtime models, it doesn't include runtime execution backends.