The types might fall into different categories. We will start with the different types of bourbon mashbills.
The most common bourbon mashbill has the required 51% corn, a secondary grain of rye, and barley.
This mashbill can be high rye (e.g., Wild Turkey, New Riff) or low ry (e.g., Elijah Craig, Buffalo Trace). The higher the rye generally the more spice is present.
The next most popular mashbill replaces the rye with wheat. So you might 51% plus corn, wheat, and barley.
This mashbill was made popular by the now defunct Stitzel Weller distillery in the mid-twentieth century with brands like Old Fitzgerald, Rebel Yell, Weller, and Pappy Van Winkle.
These wheated bourbons are still being made today but by different distilleries after Stitzel Weller shut its doors in 1972. The wheat is a softer flavor and takes premium aging well.
Let's call the last type experimental. Some distillers are more adventurous with their mashbills than others. You will have mashbills that include four grains (corn, wheat, rye, and barley), five grains, or other grains like amaranth, malted grains, triticale, rice, oat, millet, or sorghum.
The other types of bourbons would fall into a category we've touched on already — straight bourbon whiskey and bottled in bond.