for an explanation of nappy fabrics, boosters can be made of all of those fabrics. I personally prefer hemp boosters as they are the slimmest and most absorbent.
Liners provide a stay dry layer and are usually made of fleece or minkee. Some people like to use flushable paper liners on top of the reusable ones to make poo disposal easier. Some people use silk liners too when their LOs have nappy rash.