Optical (reflective: place one or more marks on the shaft or tire; break beam: one or more openings in the wheel), magnetic or inductive (one or more magnets on shaft or tire), mechanical (encoder or switches - not recommended due to wear), and probably some more that I don't think of right now. Contactless would generally be preferred.
speed of Tyre of tractor or the shaft to which it is attached with ..........high accuracy of about 2%
All of them are, and in many different versions.
All of the above have all kinds of components.