A good range of the more traditional and exotic vegetable & flower seeds available by mail or online order.  They also have an extensive range of gardening accessories as well as mail order fruit trees, berry bushes and bulbs.  Over the years I have bought seeds and other gardening products from them on a fairly regular basis.

The down side of Diggers is that they are a bit pricy, even if you pay for their membership, which entitles you to discounted prices.  Other seed mail order companies offer seeds and gardening accessories for similar or even cheaper prices without the rigmarole that's involved with becoming a member.