I have two main peripherals worth mentioning. My USB to ADB converter from Big Mess O’Wires which allows me to use a modern usb mac keyboard with my older ADB macs. Shown here in action on my colour classic.
My Asante talk is a clever little gizmo. It converts from apple talk to ether talk. Meaning my old school macs can talk to the newer Ethernet based ones. A rare eBay find.