My friend David Hobbs is ready to bring Content Chimera out of alpha. Chimera is a tool to assist in content inventory and analysis:
Content Chimera: Content Exploration and Decision-Making At Scale
I wrote a bit about Content Chimera in my post about analyzing 17 years of Gadgetopia content. Chimera offers all sorts of reports, filters, extraction and visualization to help you explore and examine large repositories of content.
David has spent most of his career in the niche of content migration and large-scale website transformation, so I suspect this tool is the result of decades of experience and frustration in that space.