Has anyone called Rally REST services from Clarity GEL Script?
We need to send/receive additional information back and forth between Clarity and Rally and looking to get that done from GEL if that is possible
Not yet in any official capacity from your own GEL scripts. Reference: Use RESTful APIs in Integrations via Process Manager (and/or GEL)
For alternative offerings, you should probably raise the question with your account team who could inform you about what is possible or available.
Also I think you should already be aware of the integrations and discussions happening about these two products through these references, but just including them for some completeness at this time: CA PPM | CA Agile Central Help and CA Agile Central Community | Ask and Engage with CA Agile Central (formerly Rally) Users