BeBRexx
BeOS port of BREXX. http://www.bebits.com/search?search=rexx
BREXX
Free interpreter for Unix, MSDOS, WinCE and Amiga. By Vassilis N. Vlachoudis. http://ftp.gwdg.de/pub/languages/rexx/brexx/html/rx.html
r4
Classic Rexx language interpreter for Windows, from Kilowatt Software. http://www.kilowattsoftware.com/r4Page.htm
Rexx Anywhere
Writing portable Rexx execs. By Dave Alcock. http://www.planetmvs.com/rexxanywhere/
KEXX
Dialect used in KEDIT (XEDIT-like editor). Summary by Rex Swain. http://www.rexswain.com/kedit.html
REXX/imc
Open source Rexx interpreter for Linux/Unix. http://users.comlab.ox.ac.uk/ian.collier/Rexx/rexximc.html
uni-REXX
An ANSI standard implementation for UNIX systems. Free sample code library. http://www.wrkgrp.com/unirexx/
REXX/VSE
Product page, including support information and samples. http://www-1.ibm.com/servers/eserver/zseries/os/vse/support/rexx/rexxhome.html
Shadow/REXX
Dialect used in NEON System's Shadow OS/390 Web Server. Described in "Programming Guide". [PDF] http://www.neonsys.com/downloads/documentation/Shadow_Web_Server/Shadow%20Web%20Server%20Programming%20Guide%20v48.pdf
S/REXX
UNIX implementation from Benaroya. Graphical debugger available. http://www.sedit.com/rexxgrph.html
SAL
Scientific Applications on Linux - REXX entry http://sal.duth.gr/F/1/REXX.html
CICS Rexx
Language and development environment. http://www-3.ibm.com/software/ts/cics/products/rexx/
Jaxo: Rexx for Palm OS
Product description, including downloads and free runtime. http://www.jaxo.com/rexx/
PC DOS REXX
PC DOS 2000s REXX Programming Language http://www-3.ibm.com/software/os/dos/psm951sa.html