Unity Graph Editor
https://github.com/alelievr/NodeGraphProcessor
https://forum.unity.com/threads/xnode-a-general-purpose-node-editor.502354/
https://github.com/Siccity/xNode
https://forum.unity.com/threads/node-graph-custom-purpose-unity-built-in-node-graph.657670/
https://assetstore.unity.com/packages/tools/utilities/relationsinspector-53147