Photo by Agiorgio - Own work, CC BY-SA 4.0
If you find something you like, just download and try it out. Most of the files are in the TSO XMIT format, though some are small and do not need any support files, they will be in plain text format.
The CBTTAPE.ORG website is where you will find the most and the best of z/OS freeware stuff. I have used a number of programs from there over the years. And contributed too.
Contact me for questions and suggestions email