Grey Norweigian is a great base fibre for felting. Not only does it give a lovely shade, varying between light and darker fibres, it's also hard wearing, useful if you're making something to wear. A great option if the softness of 70s Merino isn't required.
Micron range 30-35
Some folks like it for needle felting of 3D shapes. These wools are good for dyeing with landscape dyes either solid shades or space dyed. Using dyes on grey wools give some nice muted shade efeects
If you are looking for colours for small animals using 20gm landscape dye pots you can can create your own colour stock of shades very easily and cheaply.