Unity Inspector Tweak - [SerializeField]
While SerializeField has nothing to do with Property Drawers or Custom Editor scripting, I still wanted to include it here as it does allow you to change some of the basic behavior of the Inspector.

For people coming from an Object Orientated Programing background, it is always annoying that you can not alter the values of a private variable. Well you actually can if you use [SerializField] you can.

Here is a short video on how to use it in your own Unity Projects.