Retro hardware generally: boards, extension cards, power supplies, peripherals. Use more specific tags as appropriate; use [case] instead for enclosures.
The term "hardware" encompasses components on circuit boards, physical input devices, power supplies, displays, and other devices that contain or are components that are capable of interfacing electronically with other components or devices. It does not include plastic cases, passive mechanical components (e.g. a laptop's hinge) or non-computing parts of a system (e.g. the glass pane of a CRT display), but it does include electronic systems that have mechanical parts (e.g. a floppy diskette reader).