Noncommarcial
Squeak http://www.squeak.org/
Pharo http://www.pharo-project.org/home
Gnu smalltalk http://smalltalk.gnu.org/

Commercial
Cincom VisualWorks http://smalltalk.cincom.jp/main/products/visualworks/
Gemstone http://www.vmware.com/company/acquisitions/gemstone

See also
http://peace.2ch.net/test/read.cgi/tech/1360991429/