Wireless keyboards offer a radio frequency  solution and infrared technologies, that allows you to control the keyboard and the trackball from up to two meters (6.6 feet). RF (radio frequency) is more convenient than IR (Infrared) technology as it doesn't require you to point the keyboard at a receiver on the computer.

Ergonomic keyboards: There are 2 basic types of ergonomic keyboards- fixed split  and and adjustable split. The fixed split keyboards have the typing areas for each hand positioned at an ergonomic angle that is not adjustable. The adjustable split keyboards may have 2 or 3 separate pieces (one for each hand), that can be adjusted or separated as needed. Also one-handed keyboards are available that allow the keys and functions to be accessed using only one hand. For all users this types of keyboard will feel awkward at first, however will soon become natural.

Touchpad  keyboard has a built-in  touchpad that  allows you to perform point and click operations without removing your hands from the keyboard.

The Microsoft Natural Keyboard Elite is the second in a series of ergonomically designed keyboards from Microsoft. Its split, gently sloped design allows you to place your hands, wrists and forearms in a natural position for greater comfort while typing. With its improved space-saving design, the new keyboard takes up less room on your desktop and fits easily into keyboard trays.,

Magic Wand Keyboard: The Magic Wand Keyboard is a miniature computer keyboard, with a built-in mouse, that allows disabled people with limited or no hand/arm movement to fully access any IBM or Apple Macintosh computer. It is the only computer keyboard, and mouse, that requires no strength. ( Manufacturer: In Touch Systems )

Keyboard Internet Multi Media: The Internet Keyboard has additional programmable hot keys, which   allow you to browse the web or check E-mail directly from the keyboard. One-touch buttons take you directly to your favorite multimedia activities - navigate music and video clips, surf the Web, start the programs you use most, and more.

Datahand ergonomic keyboard helps to reduce RSI-related pain comes through requiring far less finger movement to type than do other keyboards. Each finger rests in a “well,” sort of akin to the “home row” on a traditional keyboard, except that the finger never has to leave its well. Each finger has five keys assigned to it, pressed by moving the finger north, south, east, west, or pushing down. Since a regular keyboard just uses one kind of finger motion (down) as opposed to Datahand’s five, the Datahand allows a greater variety of finger motions, reducing the repetition that can aggravate certain kinds of RSIs (Datahand corp.).

Illuminated keyboard: - Light up Keyboard is the perfect inexpensive addition to any computer.  Each of the keys is individually backlit with a light up EL film which can be turned on and off at the owners convenience. Not only do the keys light up a deep blue but the keyboard has super bright blue LEDs above the "Num Lock" "Scroll Lock" and "Caps Lock".
The Black Multimedia Illuminated Keyboard is also the only illuminated keyboard on the market with multimedia keys. This simple but great addition puts Volume Controls and Internet Commands at your fingertips. Usually drawing power from the USB port, this type of  keyboard is intended to be used in environments where there is insufficient light. For more details see: Illuminated Keyboard

Gamers keyboards built on the  the idea that gamers want a keyboard layout that is more in tune with how they play. There are the Logitech G15 keyboard, Wolfking gamers keyboards, Ideazon Zboard,  Saitek Gamers Keyboards, and so on.

Keypads: It can  be a simple numeric keypad to accompany keyboard or an advanced programmable 20 or 58 keypads.

Braille keyboard - the keys are marked with raised dots as an aid for the blind.