Fisherman’s Rib is a lovely squishy stitch which produces a warm and very stretchy fabric. It is ideal for hats as the stretchiness makes it a perfect fit for any sized head.
I knit my version in a lovely variegated organic Merino Aran weight yarn, from Felt Fusion on Etsy, but it looks equally lovely in plain coloured, tonal, or even self striping yarn.
You can buy the pattern in the Granary Knits Pattern store.