You can use this AQL query to search for entities in your listing that has a tag:

dataInstances.count() <> 0

or this one to search for those having a specific tag. In my case, the tag is ‘prod’:

dataInstances.any(displayName = 'prod')

Hope this helps!

Thank you for your question, @jdc122. 

Purpose Tag is a customer tag which can be assigned to both catalog items and monitoring projects. It is helpful when it is intended to be used in a particular monitoring project stage (the equivalent tag can be added to the relevant monitoring project).

Best practices for using Purposes Tag are following:

• indicating the affiliation of the catalog item or monitoring project to a specific environment e.g. development, test, production
• indicating the affiliation of the catalog item and monitoring project to each other
• indicating the relation of the similar tables with countries the data refers to, e.g. USA, UK, Germany.

Here are also links to documentation: Adding Data Instances, Adding Purpose Tag, Adding Purpose Tag 2

Hope it helps, don´t hesitate to ask further questions.