In order to make drum sets more competitive, the makers will often throw in inexpensive extras to give people an additional incentive to buy their sets as opposed to others. Most of these bonus add-ons are also fairly common in popular music, so they are desirable, but at the same time are cheap and simple.
One of the more common of these add-on percussion instruments is the cowbell, which can be easily affixed to your drum set’s hardware and provides a unique sound. Cowbells have been used in a lot of popular music today and offer a prime example of an inexpensive, but desirable, bonus that is frequently included with a drum set.
Another example is the ice bell, which is a tiny cymbal that creates a high pitched, pinging bell sound. Generally made of the same alloys as other cymbals, the ice bell is mostly bell shaped, with only a small, flat rim running around it. Like the cowbell, it is extremely small and can be attached almost anywhere on your drum set.
Percussion blocks are usually made of plastic or fiberglass and amount to a modern equivalent to the traditional wood block. Constituting a closed half circle, with one side being straight and flat and the other being curved, modern percussion blocks are very small, easily attached and create a unique sound.
Percussion tubes are very similar to percussion blocks, except they are smaller and fully tube shaped instead of being half circular like the blocks. Percussion tubes, like percussion blocks, are usually made of plastic or fiberglass. The tubes usually arranged as a set of tubes ranged side by side with each tube being a different length and therefore creating a different tone.
Mounted tambourines also fall into the category of add-ons, though they are not as common as many of the examples given above. These are essentially normal tambourines, but come with a mounting option that allows them to be attached to a drum set’s hardware. Played with a stick like any other drum, these tambourines have a very unique sound that gives the drummer an unusual option.