I just released a new Windows Shell Extension - SmartRename. It allows for simple search and replace or regular expression bulk renaming of files and folders. I actually first wrote this extension back in 2007 after Windows Vista shipped. It was supposed to be included in the Windows Vista PowerToys to showcase the capabilities of the new file operations engine in Vista - which I worked on at the time. Unfortunately, the Vista PowerToys got cancelled just as I finished it :/. I had always wanted to get around to rewriting the extension from scratch and releasing it. Finally after 12 years I found some time.
Code and installer available at the SmartRename Repo Page: