With the advent of PropertyDrawer in Unity 4 this is possible to carry out setting the appearance of objects in the Editor. The basis of the collection is the examples found in the vast Internet, revised and updated with my own work.
The plugin is available at www.assetstore.unity3d
Property Drawer Collection adapted to the Unity 5

Online documentation here is Docs.
Site project here.
Were fixed bugs:
- The output of the properties as elements of the array,
- sizing controls,
- identified problems of compatibility, etc.
Improved interface for working with drop-down lists, select values. Added raw version of a system error notification filling properties.
Examples of other developers and own experiments have helped to extend the scope of PropertyDrawer:
- Output fields.
- Use DecoratorDrawer for design.
- output of SerializableObject.
- generation of EditorWindow with using GUILayout to form interface.