This plugin has been integrated into BSK Forms Blacklist.
Contact Form 7 Blacklist is different from WordPress' Comment Blacklist, the comment blacklist will let entries in but mark as spam while Contact Form 7 Blacklist let you have more options to control visitor's submissions.
It was built to help ban submissions from users using spam data or competitors info to create new entry to your site. This plugin allows you to validate a field's value against the keywords and email addresses that you added in admin area.
Site admins can create a list of items( keywords ) or email addresses and apply the list to a Contact Form 7 field. If the filed value match any of items( keywords ) then it will throw validation error and block the visitor from submitting. Yes, you may chose to keep silent but discard the submission. Or skip a notification.
Please check more details here >>