Not a PlugIn, but…
Just discovered PlugInfo: Audio Plugin Explorer | Apple Silicon | ThinkerSnacks.com while trying to figure out, which of my plugins are still not M1 supported.
Fair price, useful 
BTW: I just reworked my little Python script mentioned some time ago in I'm looking for whatever file that keeps the list of plugins/VSTs that GP has found before - #8 by tripleB to readout any gig file to provide an Excel-list which can be filtered in various ways.
GPpyTools.py.txt (4.4 KB)
Just remove the .txt extension and run e.g. in a suitable Python environment like Visual Studio Code.
With some minor adjustments in Excel (column sizes, adding filters) this is quite useful for me to find specific Plugins in my gig files I want to replace…
[edit] I put it also on my private Github GPpyTools (Github)