There are a few types of felt readily available to work with, alongside needlefelt which you can create yourself.
This is the oldest form of felt (or fabric at all) that is known to man, it even predates knitting and weaving techniques. It’s the most common type, which uses wool fibres or a blend of wool and synthetic fibres which are compressed using heat and moisture, causing the fabrics to interlock. It can be cheap to make, and can also be made in a range of thicknesses which achieve a high density.
In the case of needed felt, a blend of wool and synthetic fibres, or 100% wool, are again interlocked but this time by a machine rather than naturally. Machines that contain thousands of needles interlock the fibres to produce this softer, less dense type of felt fabric which is often used for crafts or cushioning.
To make woven felt, wool or a wool blend is directly woven into a cloth and then moisture and pressure are applied. This makes the fibres naturally interlock, as with pressed felt. This incredibly durable fabric is ideal for musical instruments and door seals, and has a much lower maximum thickness than