I have a number of add-ons installed in 2.8, import/export, mesh, etc. They don't show up in the appropriate menus, however. For instance, I have the 'official' add-ons: BVH, FBX, STL, OBJ and VRML2 installed and enabled but when I go to the import menu all I am offered is Collada(dae) and Alembic (abc) which are not actually even add-ons.
Am I missing some 'switch' or something or is this a bug? I can't believe this is general behaviour or there would be more 'noise' in these forums. The only thing I see is a 4 month old - and unanswered - query which sounds similar to mine!