Atco Toys
   Produces a large variety of building block sets and construction toys. Provides links to sales offices.
   http://www.atcotoys.com/

DIDA Development
   Makes educational electronic toy brick. Taiwan.
   http://www.dida.ttnet.net

Han Nam Corporation
   Producing plastic building block toys in Korea since 1990.
   http://hannamcorp.en.ecplaza.net/

Kiblo
   3D building blocks designed for infants and toddlers.
   http://www.kiblo.com/

Learning Materials Workshop
   Designs building toys using hardwood blocks, acrylic prisms, and flexible forms that develop children's thinking and imagination.
   http://www.learningmaterialswork.com/

Lego Company
   Producer of building blocks.
   http://www.lego.com/

Ritvik Mega Bloks
   Canadian manufacturer of construction block sets for infants and children to age 12.
   http://www.megabloks.com/

ThinkWorks
   Creates and sells educational block toys such as magnetic or mosaic games. USA.
   http://www.thinkandthrive.com