[fragmede]

raspberry pi's support USB gadget mode, and can thus emulate USB storage with the right connector.

TTL-level serial port pins exist as well.

[pests]

This is how the PiKVM works. It pretends to be a hub with an attached mouse/keyboard (and optionally a flash drive/storage)

Then optionally you can connect your motherboards power/reset pins so you can reboot or turn off remotely.

Video is a third party HDMI capture card that plugs into the Pis camera port.