These examples are designed for Unity. I'm programming using Unity because its ease of programming and flexibility let me focus on rapid prototyping and experimenting with new ideas in game development, VR, and interactive tools.
Hierarchy Separator
This Unity library will help you create aesthetic hierarchy separators for your Unity scene inside the Editor.

Install via Unity's Install package from Git URL option using:
gavwood/HierarchySeparator.git
Full source available on GitHub.
Editor Notes
In Unity projects, there is often no standard way to attach documentation or project notes. Some teams create "Documentation" folders, others use "Documentation~", and practices can vary widely between projects. EditorNotes helps you standardize how and where you store important notes, references, and documentation inside your Unity projects. It provides a simple, lightweight editor window for writing, saving, and easily accessing these notes directly within the Unity Editor.
Quick Access to Documentation Folders
EditorNotes provides shortcuts for creating a standardized "Documentation" folder in your Unity project. It also lets you quickly open the documentation folder, the project root, or the parent directory.

Editing and Managing Project Notes
The built-in editor window allows you to edit and manage notes directly inside Unity. You can quickly jot down important project information, as shown here with placeholder text from Lorem Ipsum. You can save these into your newly created documentation folder and keep safe with source control.

Install via Unity's Install package from Git URL option using:
gavwood/EditorNotes.git
Full source available on GitHub.