If you are looking for a REXX tool to expand the PROC in the JCL. And also to find all input, out datasets and get GDG details used in the JCL, then I think below blog post has it.
https://atomkpadhy.blogspot.com/2013/04/jcl-expansion-tool.html
REXX Tool – JCL Expansion (PROC, INCLUDE) – Get dataset
03 Tuesday Apr 2018
Posted in REXX
