Typing in ‘Hair’ at the top of the Content Library tab shows all hair in your listed runtimes. It is even more useful now that many of them are marked ‘Material’ or ‘Pose’ which is what you are asking for.
It only shows about 1/4 of the hair I have installed. For instance, it will show the materials for some items not the actual hair.
When I search for just hair, it also finds chair poses for some reason, and Jaime’s eyes, several face textures etc.
To me it is kind of useless.
None of the stuff in say… Genesis Starter Edition shows up in the ‘hair’ search even though several hairs came with that installer.