ATKColoredExpander

ATKColoredExpander, a free and Open Source compressor plug-in, for 64-bit Mac OS X (10.9 minimum) and Windows (32 and 64-bit) in VST2, VST3 and AU plug-in formats.
The plugin now use the JUCE framework and is optimized for SSE4.2 processors on MacOS and AVX processors on Windows.
This plugin requires universal runtime libraries on Windows as per Microsoft recommendation (see the blog post for more details).

http://blog.audio-tk.com/2017/11/28/announcement-atkcoloredexpander-2-0-0/