I’ve made a few things that are useful to me, and may be useful to use. These are made for use with the Unity Game Engine and Editor.
This tool makes it easier to place tilesets by letting you just paint them directly in the scene. There is a small amount of setup for each tileset, and it does have to be placed in the resources/tileset folder, but still works great. It uses the sprite object (added in unity 4.3, so must be at least that version of unity or higher.)
I made this program to use multiple versions of unity and do project management outside of Unity. You can add multiple version of unity, change the built target on launch, as well as launch multiple projects at the same time without having to do command lines or other tricks. There is a free and paid for version, but all the paid for version does is remove ads.