I created a workaround for the "Set Variable Value" Service Catalog Step which allows you to effectively set List Collector Variable Values without having to add the "glide_list" attribute.

See this KB https://support.servicenow.com/kb?id=kb%5Farticle%5Fview&sysparm%5Farticle=KB0713770

Fork this repository: https://github.com/kr4uzi/ServiceNow-ATF-Plus

And import your newly forked repository to a instance of your likings.

The following new ATF Step will be available:

I plan on adding more "Bug Fix" steps in the future, so stay tuned.