Glamorous Toolkit - Moldable development environment. (Web)
Smalltalk-87 (HN)
Smalltalk-80 - By the Bluebook implementation of Smalltalk-80. (Lobsters) (HN)
Smalltalk-72 - First operating Smalltalk system.
RoarVM - Manycore SqueakVM.
TruffleSqueak - Squeak/Smalltalk VM and Polyglot Programming Environment for the GraalVM.
Domains - Computational algebra system in Smalltalk.
The Smalltalk Zoo (2020) (Web) (HN) (HN 2)
SOM (Simple Object Machine) - Smalltalk dialect which is file-based and independent of the Bluebook bytecode and interpreter. (Web)
ohm-som - JavaScript implementation of SOM, a minimal Smalltalk for teaching and research.
Dr.Geo - Interactive Geometry in Smalltalk.
Seaside - Framework for developing sophisticated web applications in Smalltalk.
Strongtalk - High-Performance Open Source Smalltalk With An Optional Type System. (Code)
Squeak - Free Smalltalk System – On RISC OS.