The Construction Site  
   A large variety of construction toys including brand names such as t.c. timber, K'nex, Lincoln Logs, Tinkertoy and Exin Castles.
   http://www.constructiontoys.com/

Lumiere Link  
   Building toy is transparent and free-form. Illinois, USA. [order online or by fax, phone or mail]
   http://www.lumierelink.com/

Atollo  
   Flexible models, from articulated figures to geometric space structures.
   http://www.atollo.com/

Wedgits  
   Wedge shaped building blocks construction set. Includes design ideas and worldwide list of dealers.
   http://wedgits.com/

Gridblox  
   Cubical wooden blocks with notched corners that interlock by gravity.
   http://www.aptitude-testing.com/gridblox.htm

Astro-logix  
   Create complex and beautiful fractal stars and 3D geometric shapes.
   http://www.astro-logix.com/

Link-Kit  
   Also known as Omagles, a building toy to create an unlimited variety of child-size toys for climbing, riding or pretending.
   http://www.omagles.com/

Kapla USA  
   Wooden construction blocks from France, with a long thin shape, and books with suggested projects. Provides photo gallery of museum exhibits, and workshop information.
   http://www.kaplaworld.com/