I made this simple Python program for Windows which I’ve released under the GNU public licence to fill a gap missing in Steam, the ability to move an individual game from one steam library to another.
Close Steam down, point this script at your old and new steam libraries, choose the game you want to move from the list and hey presto your game is in the new location.
Great for if you need to free up space on your drive but you don’t want to move your entire library to another location.
Use this at your own risk, it’s only been tested on my machine and I’ve only covered a few things that could go wrong.
Any assistance in improving the quality of the code would also be greatly appreciated.
https://sourceforge.net/projects/pysteamgamemover/
Download steam-gamemove.py if you already have Python 3.5+ installed, if not download the precompiled version at /dist/steam-gamemover-v0-1.zip.
You may need to download and install the Microsoft Visual C++ Redistributable for Visual Studio 2015 (https://www.microsoft.com/en-gb/download/details.aspx?id=48145) if you wish to run the precompiled version on Windows prior to Windows 10.