If the underlying upholstery is good, you may just need a new cover. Or perhaps a refurbishment where only some of the existing fillings and fabrics are removed and replaced with new.

If you have modern piece, ie post 1950, that needs complete re-upholstery it is probably best done using modern materials, similar to the ones it was originally upholstered with.

If you have an older piece which needs complete re-upholstery it probably deserves to be done using traditional stuffings and techniques.

Various cushion styles:

Box cushion, T shaped, Bolster with pleated or flat end, scatter cushions and bench cushions also available.