The top board is the USB keyboard/mouse adapter.
The middle row has the pass-through boards I made which just convert the old external connectors to 0.1 inch headers. The 2nd connector board is a fragment from the original Mac motherboard which I cut out with a dremel, since I couldn't find anyone who sells the DB-19 connector any more.
The lower board is also a fragment from the original Mac analog board, this one cut out with a hacksaw. It has the original power switch, power jack, and battery holder. I re-wired the power switch and jack so they feed a small power strip.