As is known to everyone, yarns can be made into various woven labels. The most common plant fiber is cotton, which is typically spun into fine yarn for mechanical weaving or knitting into cloth. The most commonly used animal fiber is wool harvested from sheep. For hand knitting and hobby knitting, thick, wool yarns are frequently used. More rarely, yarn may be spun from camel, yak, possum, cat, dog, wolf, rabbit, or buffalo hair, and even turkey or ostrich feathers. Natural fibers such as these have the advantage of being slightly elastic and very breathable, while trapping a great deal of air, making for a fairly warm fabric.

Spun yarnis made by twisting or otherwise bonding staple fibers together to make a cohesive thread, or "single. Twisting fibers into yarn in the process called spinning can be dated back to the Upper Paleolithic, and yarn spinning was one of the very first processes to be industrialized. Spun yarns may contain a single type of fiber, or be a blend of various types. Combining synthetic fibres with natural fibers is very common. Blends of different natural fibers are common as well, especially with more expensivewoven labels such as alpaca, angora and cashmere. Bamboo yarn is a less expensive yarn that is a recent innovation.

Other natural fibers that can be used for yarn include linen and cotton. These tend to be much less elastic, and retain less warmth than the animal-hair yarns, though they can be stronger in some cases. The finished product will also look rather different from the woolen yarnswoven labels. Other plant fibers which can be spun include bamboo, hemp, corn, and soy fiber. Yarns are selected for different textiles based on the characteristics of the yarn fibers, such as warmth (wool), light weight (cotton or bamboo), durability or softness. Acrylic yarn is the least expensive.