Rexx/ISAM - Interface to ISAM files. - http://rexxisam.sourceforge.net/
rxJava - Rexx functions for Java. - http://rpm.pbone.net/index.php3/stat/4/idpl/56083/
Rexx/CURL - Interface to the cURL package for access to URL-addressable resources such as web pages, ftp sites, and telnet sessions. - http://rexxcurl.sourceforge.net/
Rexx/Curses - Interface to Curses, a Text-mode user interface. - http://rexxcurses.sourceforge.net/
Rexx/Wrapper - Build executable program from Rexx programs. - http://rexxwrapper.sourceforge.net/
LesTec Pty Ltd - Modular And Integrated Design (MAID) for Windows and OS/2 (visual Rexx GUI) and input/output function library. - http://www.lestec.com.au/
Rexx/gd - Interface to manipulate simple graphics images. - http://rexxgd.sourceforge.net/
dbfREXX - Database functions for dBASE, Foxpro, Clipper. - http://www.dsoftusa.com/dbfrexx.htm
Rexx/SQL - Interfaces to many SQL Databases. - http://rexxsql.sourceforge.net/
Rexx/Tk - A library for using the Tk GUI toolkit. - http://rexxtk.sourceforge.net/
Rexx/Trans - Rexx API translation library - http://rexxtrans.sourceforge.net/