Tiny flat dolls, motifs, embellishments, ornaments, pins —— these little people may be many things.
Use any yarn you choose and select a hook a size or two smaller than that recommended for the yarn weight, so it can be worked firmly.

Using a D 3.25 mm hook with dk, they are approximately 4.5”
Using fingering and a D they are approximately 4”.
Using F/3.75 mm they are about 5”

I’ve made them in wool and flted them to make earrings.