drscheme - Scheme Programming Environment
elk - the Elk Scheme interpreter
gauche - A Scheme implementation designed for script writing.
guile-1.6 - The GNU extension language and Scheme interpreter
mit-scheme - The MIT/GNU Scheme development environment
mzscheme - Rice University PLT Scheme Interpreter
oaklisp - An object-oriented dialect of Scheme.
rscheme - Threaded, persistent, OO, scheme interpreter and compiler
scm - A Scheme language interpreter.
stklos - An efficient Scheme System providing a powerful Object
System
scsh - A `scheme' interpreter designed for writing system programs