thebluecube

This plugin adds some additional features to the Gravity Forms plugin:
<ul>
<li>Input ID change (if the form has not received any entries yet)</li>
<li>Advanced input validations</li>
<li>Form access control</li>
<li>Advanced conditional logic shortcode to be used in email notifications</li>
</ul>
Documentation: https://thebluecube.com/wordpress-plugins/bluecube-mighty-gravity-forms/documentation/

Blue Cube Mighty Gravity Forms

This plugin adds some additional features to the Gravity Forms plugin:

brainvireinfo

This plugin adds custom validation messages to individual fields of your contact form 7. You will be able to add your custom error message for every field like text, radio, select, textarea, etc.. in contact form 7.
Features of this plugin.
<ul>
<li>Supported with WPML (Contact Form 7 Multilingual) addon</li>
<li>Add Custom Validation Message to Contact Form Fields.</li>
<li>Allows you to set Different Error Messasge for text, text area, email, URL, radio, phone number, and more fields.</li>
<li>Error message for individual fields.</li>
<li>You can add custom validation with multiple forms on different pages or single page.</li>
</ul>

Custom validation error message – CF7

This plugin provides custom error messages for each field in contact form 7. Also, this plugin supported to "Contact Form 7 Multilingual" addon.

Blue Cube Mighty Gravity Forms vs Custom validation error message – CF7