network card (wired and wireless), sound card, Firewire and USB card, Video, Controller, Parallel printer card, etc...
here are some wireless cards:
http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&N=100010074%20600014290%20600014300%20600014293&IsNodeId=1&Description=pci%20wireless%20card&name=32bit%20PCI2.2&Order=BESTMATCH