A more complete list can be fou nd here. 3dfx is a platform for 3d gaming. 3dfx chipsets allow gamers to play graphic-intensive 3d games with a high degree of control and realism. Some kind of 3dfx chipset is now shipped with all 3d cards. A true gamer cannot go without such a card.
Cards are available almost anywhere.
If you are wondering if a card is capable of intense 3d work, check the box for the 3dfx logo. Additionally, there are several great websites that can help choose the right card for you.