Requires Unity 5.3.6 or higher.
Update 2.0 Now supports rotated box collider generation!
Easy collider editor is designed to facilitate the creation of 3D primitive colliders. By using primitive colliders instead of mesh colliders, rigidbodies can be added to gameobjects to allow for physics interactions.
This tool allows for easy addition of multiple 3D primitive colliders on gameobjects by using simple and easy to use vertex selection tools. No more painfully adding, moving, and resizing colliders.
More details can be found on the release thread at the Unity forums.