The most commonly found willow is usually Goat Willow, which has the type of 'pussies' we associate with willow and grows very tall.
I don't know the name of the type used for biomass for boilers, but sections of plants are readily available for planting.
The willow used for basket weaving is Osier, grown on an almost industrial scale in the SW. Locally however, weavers may have a need for willow with coloured stems. There are many of these, from bright scarlet and yellow through to blue. Growing stock for these in small quantities is available on Etsy and from the second year you can propagate your own. You would need to learn how to grow and cut willow to be suitable for weaving.
Once you have a coppice planted up you could sell on propagation material yourself.
I don't know the willow type used for growing structures such as woven hedges, kids living gang huts, living picnic spots etc (probably goat willow) but selling pieces for people to grow their own could be a market.
if you keep sheep then 'tree hay' can be made from willow for winter fodder and fresh branches can be fed all year round to provide micronutrients and forage.
There are also many, many species of willow which are worth growing just for their beauty and variety. They will help to dry out the sogginess from your parcel of land - we use them here for the same purpose.