The Fnc-2 Attribute Grammar System  
   An attribute grammar system based on strongly non-circular AGs that perform extensive space optimizations
   http://www-rocq.inria.fr/oscar/www/fnc2/littlefnc2.html

Ox Grammar System  
   An attribute-grammar compiling system based on yacc, lex, and C, the system embodies a yacc/lex/C preprocessor designed to bring attribute grammars to the mainstream of UNIX-based language development. It can also be used with Bison, Flex, and C++.
   ftp://ftp.cs.iastate.edu/pub/ox/

The lrc attribute grammar system  
   The system generates efficient incremental attribute evaluators and was written by one of the attribute-grammar formalizers.
   http://www.cs.uu.nl/groups/ST/Software/LRC/

Micro Attribute Grammar System  
   The UU_AG system is a very simple program that reads a set of files containing an attribute grammar, in which semantic functions are described through Haskell expressions.
   http://www.cs.uu.nl/groups/ST/Software/UU_AG/index.html

WAGE  
   The implemented programming language is based on an attribute grammar.
   ftp://ftp.cs.uwindsor.ca/pub/wage/

The AGFL Grammar Work Lab  
   The formalism for the to attribute grammars related Affix Grammar over Finite Lattices developed at the University of Nijmegen is being applied to natural-language processing. Context-free grammars can be described on a primary context-free level augment
   http://www.cs.ru.nl/agfl/