Dependent ML: DML: Conservative ML extension, has type system to enrich ML with restricted form of dependent types, to allow many interesting program properties: memory safety, termination can be captured in type system and thus be verified while compiling. Description, code samples, downloads.
Extended ML: EML is a framework for specification and formal development of Standard ML programs. Description, publications, tool support, education resources.
ML Kit: Standard ML compiler.
MLRISC: Framework for customizable, retargetable and optimizing compiler back ends, written in Standard ML. Successfully retargeted to many architectures. Deals elegantly with special requirements imposed by execution model of different high-level, typed languages.
MLton: Whole program optimizing compiler for Standard ML.
Moscow ML: ML system for DOS, Linux, Windows.
Open Source Release of MLj: SML to Java bytecode compiler, based on Persimmon's MLj.
Poly/ML: Standard ML full implementation: compiler and environment, has libraries for MS Windows, X Window. [Open Source]
Standard ML of New Jersey: SML/NJ is a compiler and programming environment for SML, with associated libraries, tools, documents. Descriptions, news, downloads (Unix, Windows), literature lists, FAQs, links, contacts. [Open Source, Lucent]
The Alcool-90 Experiment: Experimental ML extension with run-time overloading and type-based notion of modules, functors and inheritance. Large HTML text document.