Support for Lists to have custom string values or other types

It would be awesome if lists could support other types of values besides just IP addresses.

My Use case:

I would like to check a specific header against values in a list in the WAF rules.

It should be flexible enough to use against most field types in the WAF option to check for a set of common values.

We have 14 zones so having an inline list replicated 14 times is not ideal to manage.