I would like to make a variable in a workflow to specific content in a column I call Parent List ID. However, when I try, the only dynamic content options I get are for the item ID. Why do I only get that one option? Do I have to use an expression to get the information from the right column? I tried using the item function, but that doesn't work.
Is your ParentID column on that list set up as a number type field?
I set mine up as a number type field with zero decimal places, and you can see that it is available in the dynamic content selection box:
I'm fairly sure what's happening is that when you specify the type of the variable, SharePoint/Flow is filtering out the available choices in the dynamic content to only ones of that same type, so you don't mismatch and throw errors.