I've found what's available varies over time. However, if you can find it in a rather 'blonde honey' color as a starting point, that's what's worked best for me. I did find some very dark brown stuff that I'm going to explore how it turns out (steep sale price - like 80% off).
Oh, and ask at yardage shops for 'fake fur', not just teddy bear fur.
One trick I am going to use is a cheap pair of hair clippers I got at a swap meet to trim the fur to shorter lengths (or even down to the supporting cloth to run a road through a piece of fur). One of the challenges for me is that even short fur (which can be a challenge to find) is still too high for 15 mm figures so that will be a welcome technique.
The honey cloth, hit with a variety of spray paints to give color variation works the charm - but leave it outside in sunny, dry conditions for a bit because the smell will linger for a long time (like years!).
I've also experimented with putting pieces on hard bases for easy to set up 'flavor' terrain but some unmounted pieces are good for draping over varying elevations of terrain, too.
If you do find something you like, buy as much as you can possibly imagine using because the chance of finding it again goes way, way down. I speak from experience!