Mouse
There are basically 4 different kinds of mouses available to people who use retrocomputers
- serial
- PS/2
- USB
- Wireless
As often motherboards predating Socket 7 lack USB (and older ones may even lack PS/2), a serial mouse is almost a must for playing older Windows games, but these are hard to come by these days (particularly mouses that have a scrollwheel). Adapters to make a PS/2 mouse fit in a serial connector exist, but the mouse itself must be able to support the serial protocol or it won't even work. PS/2 expansion cards are virtually non-existant, if they exist at all and USB expansion cards have the drawback to requiring a relatively large amount of CPU power (so it's not always a good idea to use such a card in a 486). On top of that, many USB cards won't fit a 486's PCI slots as said PCI slots often are incompatible with newer USB expansion cards.
Wireless mouses are generally not recommended for a retrocomputer, though this may depends for a great deal on individual preferences