Switches
Switches connect computers by deciding which computer to send data to.
Hubs
Hubs send data to every computer connected. Commonly used today for wireless communication because of the inability to send radio waves to a specific device.
Routers
Routers connect networks together, generally the LAN to the internet.
NICs
Network Interface Cards attach to the computer, usually internally, for network connection. Can connect wirelessly and over Ethernet or via USB connection.