Templates for ads for things like brand taglines.
Additionaly to that it would also make sense to have templates/constants like USPs or call to actions that one can use in the ads. A flexible solution would be nice where a user is able to create multiple of those constants and name then individually.
For example:
USP_1 = Free shipping
USP_2 = Over 1.000 products in stock
USP_3 = 30% discount
CTA_1 = Buy now
CTA_2 = Shop now
PHONE = 555 000 000 000
All in all your tool ist greaaaaaat!! :)