If you like vintage design furniture you should really check out Neef Louis. You will find Neef Louis at the North side of Amsterdam (where you will also find Noorderlicht and The Ijhallen). So even though it is quite a journey to the North, it is worth it!
Neef Louis is a gigantic place and it’s absolutely stuffed with all kinds of old, vintage and design furniture. I would really love to be able to buy just all of it! Unfortunately my budget doesn’t allow me to do so. But still, I love to look around and it gives me inspiration.
Across the road you will find Van Dijk & Co which is much the same but with more classical types of furniture. Also worth a look!