1. Network interface cards
2. Patch panels
3. Switches
4. Routers
5. Layer 3 switch/router hybrids
6. Firewalls
7. DSU/CSUs/other layer 2 hardware
8. Application (layer 7) switches like BigIP
9. Debugging/monitoring tools like Etheral, Observer, and Sniffer
10. Cable systems - Cat 5, Coax, etc.

 Different type of network solutions needs different type of hardware.
Most common ones are:

802.11 xx standard Ethernet
Cross cable or cat type cables which is used for connection computers.
Coaxial antenna used for an unbalanced feed line.
Terminal server for providing terminals.
Router for packet routing purposes.
Catalyst switch for network switches.
Security agents for managing security.
Access points for wireless network
Network interface cards for communication
File servers db servers and storage servers.
Bridges for data brod purpose.