This page has a list of some of the places I get supplies from. It is not an exhaustive list (and I will add to it as I go along)! I am not responsible for the content of third party websites. These are not affiliate links.
Feltmaking
World of Wool – wool fibres in a huge range of colours, along with speciality fibres and felting equipment
Adelaide Walker – has a wide range of fibres for feltmaking (including quite a few native sheep breeds), equipment (including the palm washboards that I use) and lots of books
Sheepfold – a Cumbrian company specialising in British sheep breeds, a good source of a wide range of native breed wool
SkyBluePink Designs – wool fibre in beautiful colour blends
The Threshing Barn – a brilliant shop in Reeth that stocks wool and other fibres in wonderful colours, along with equipment (lots of weaving and spinning equipment as well)
Embroidery
Paint-Box Threads – hand-dyed cotton and silk threads (the colours are stunning)
21st Century Yarns – hand-dyed cotton, silk and wool threads
Linladan – linen threads (the company has a fascinating story)
Appletons – crewel wool for embroidery (lots of stockists, the Viking Loom near York is a local one)
West End Embroidery – a range of specialist cotton and silk threads
John James Needle Guide has a very useful needle guide available to download which covers the different types of needles and what they are used for
Natural Dyes
Wild Colours – dye extracts, mordants and lots of information