Nembrini Audio Wah is modeled on the Wah pedal created by Thomas Organ* Company and manufactured by JEN in Italy. This is the unmistakable wah tone heard on Hendrix classics like “Up From the Sky,” “Voodoo Child (Slight Return),” “Little Miss Lover” and “Still Raining, Still Dreaming.”
VST2, VST3, AU
Note there are more free plugins from Nembrini.
I mentioned only the wah pedal, since it is new. As you mentioned, they have several other nice freebies, like the Chromatic Tuner. $137 is a bit steep for the Black Ice Beta Gamma bass amp sim, but their 70% Cyber Week sale runs through the 4th (3 more days). Note that Nembrini Audio developed some of the excellent brainworx plugins.
I’m still new to plugins (well just use them for a few months).
I downloaded a big bunch of VST plugins in the last weeks, trying them.
So far I have like 700 (is that much?) … but around 160 do not work, probably because I didn’t install them correctly or in the wrong directory or something like that. I messed up a bit with VST2/3 and 32/64 bits 
But it’s unbelievable how many good free plugins exist (although I don’t regret the ones I bought).
It says something in a review on their site about not being able to using an expression pedal to control it. Have you tried that?
You can. There’s a Filter parameter you can map to a widget.