This month Stylecraft have released a shade card for their very popular Special DK range, so I ordered one (from Wool Warehouse) and it arrived a couple of days ago. I've used this yarn before, and it comes in an excellent range of colours, is a good basic yarn, and is very good value for money. It's great to be able to see the colours in all their glory, and I'm going to have a great time project planning this weekend.
I saw on Ravelry a month or so ago that Artesano have decided to make their yarns exclusive to their website. To make up for the fact that there is no longer anywhere that you can go to squish their yarns, they are happy to send out sample cards for their full range, as well as mini skeins so you can have a proper feel of their yarns! This approach will definitely encourage me to order from them - I love the feel of their sock yarns, and the colours of their hand-painted ranges are amazing!
Another company who routinely send out shade cards are Bergere de France. I ordered some yarn direct from them a couple of years ago,and since then have received a couple of excellent look books, complete with yarn samples for many of their yarns. When a new one arrives I merrily lose a couple of hours browsing.
So yarn companies, yes please to more shade cards!