My free downloads and Unity assets are on this page, as well as some info for my (non-free) Unity asset Resolution Magic 2D, which makes it easy to scale your 2D Unity games to look great on all devices and screens.
Resolution Magic 2D (not free, but cheap)
Without Resolution Magic 2D:
With Resolution Magic 2D:
Navigation Helper (100% free, public domain code)
My first free Unity asset is Navigation Helper. It adds a simple way to navigate between Unity scenes and pass parameters.
You can navigate to a scene like this:
Then a script on the new scene can access the parameter. You can also go back to the previous scene easily: