While there are countless types of ergonomic keyboards, the most common are typically going to be angled keyboards and split keyboards. Angled keyboards, often referred to as “Alice”-style keyboards in the mechanical keyboard world (named after the TGR Alice), split the alphanumeric keys along the middle, positioning the two halves at an angle from one another while keeping the modifier keys (backspace, enter, shift, and so on) in their standard positions. The angle will vary between keyboards, as will the number of keys, but the main constant in an Alice-style keyboard is that, despite the halves being separated from one another, the keyboard itself is not split. It has one case that all of the keys are held in.
Alternatively, a standard split keyboard does the opposite: A standard split keyboard will keep all of the keys in their standard position (with no new angles) and instead cut the entire keyboard in two, creating two distinct halves that can be moved independently of one another. Some of these keyboards will connect the two halves with a cable, while others will connect them wirelessly. This typically allows for the two halves to be angled, to sit far away from one another, or for only one half to be used (typically for gaming).
Outside of all this, there are also ortholinear keyboards. On a typical keyboard, the keys are staggered instead of being aligned upon a perfect grid. But with an ortholinear keyboard, the keys are aligned along this grid. While this can be more difficult to type on at first, it theoretically enables your fingers to move more naturally, directly up and down to reach other keys instead of moving at an angle. There are both ergonomic and split ortholinear keyboards, and keyboards that use nonstandard staggering instead, like the Naya Create.
