We need a report that can tell us which custom forms have logic-driven fields within them and possibly a count of logic driven fields within each form?

You're not going to get the exact report you want, because Workfront's backend code doesn't store display logic rules on the custom field. Instead, it stores display logic rules on the form. The closest you can get to what you are describing is, "show me forms that use display logic, and how many display logic rules exist on each form." So you may have one field on the form that has three different rules applied to it, and this report will show "three rules" instead of "one field" because Workfront is counting the rules, not the fields. This can work better to inform how light or heavy a form is on display logic.

This is a Custom Form report in your report builder. You need to know how to add a text mode filter and text mode column in your view. I won't explain that because there are hundreds of other posts here that talk about it.

The filter for your report is:

EXISTS:a:$$EXISTSMOD=EXISTS

EXISTS:a:$$OBJCODE=CTCSRL

EXISTS:a:categoryID=FIELD:ID

EXISTS:a:ruleType=DISPLAY

And you'll need to add this column:

displayname=Rule IDs

listdelimiter=<div>

listmethod=nested(categoryCascadeRules).lists

textmode=true

type=iterate

valueexpression={ID}

valueformat=HTML

This will display a list of only custom forms that use any display logic. The number of long guids in the "Rule IDs" column equal the number of display logic rules used on the corresponding form.