The world biggest seed collection, with many rare plant varieties
Amazing the number and variety of plants they have.
Nice UK company selling non-hybrid varieties and many rare vegetables.
They sell interesting things like the strawberry spinach
This company too (and organic, but it's US)
More UK companies, they all have crazy varieties, organic and non-hybrid
More focused on herbs: http://www.
Wild flowers: http://www.
All kinds of flowers: http://www.suttons.