There is such a thing as craft historical re-enactment – it’s not all Vikings and Romans. Craft historical re-enactment can happen on its own, often in living history museums, but also in conjunction with the sword and sandals kind of re-enactment*. There are also many knitters who are interested in historically-accurate crafting – there’s large and active communities of Historic Knitters and Spinners on Ravelry, for example, and another dedicated group of crafters who are preserving old, out-of-copyright patterns and crafting books online.
So, how would people have carded fleece to make yarn in the pre-industrial era?
I’m sorry this is such a poor-quality image – I took it with my phone at my first-ever wool festival, and, while camera quality is my main criterion for buying a phone, that phone was high quality for 2009. These are carders: the pair at the front are relatively modern, but at the back, on the cross-shaped handle, is a typical pre-industrial carder. Those fuzzy blobs you can see are the seed heads of one of the Teasel species of plant:
Historically, Fuller’s Teasel seeds were used for both carding wool for spinning, and for finishing woven cloth by brushing and softening the surface.
* – In my LH characters of Jodis (formidable matron) and Finnbogi (beardless and somewhat inept young warrior), my craft skill was naalbinding, a kind of Viking knitting but with a sewing needle.