VOSS
Adds transparent persistent object transaction processing to Smalltalk, allowing the application developer to concentrate on the application rather than the mechanics of storage.

MinneStore
Free object-oriented database management system for Dolphin Smalltalk/98, Visual Smalltalk, VisualAge Smalltalk, VisualWorks Smalltalk, Squeak. Provides storage and retrieval of complex Smalltalk objects.

GemStone/S
A platform for developing, deploying, and managing scalable, high-performance, multi-tier applications based on business objects.