Is there a plug-in for making specimen pages? I have Word-o-mat which is excellent, but I’m hoping to show all the glyphs in a few pages.
Just select all glyphs with a Unicode Value (you can set up a smart filter for this), copy and paste them in a design app you like.
It does not give you OT variants though. There is a mekkablue script called Test > Copy InDesign Test Text that lists all substituting features and tries to guess the affected characters. After pasting in a DTP app, you would only have to select each paragraph and activate the respective OT feature.
If you’re OK with a command line tool, you might try this:
https://bitbucket.org/LindenbergSW/FontDocTools/src/master/GlyphDump.md