Get all Gravity Forms with CSS Class. Blog post is here: https://kellenmace.com/get-all-gravity-forms-with-css-class/

get-all-gravity-forms-with-css-class.php

<?php

/**
 * Get a list of Gravity Forms whose fields have a CSS class.
 *
 * @param string $css_class The CSS class to search for.
 *
 * @return array The list of forms in this format: [<form ID> - <form title>] => <array of fields that have CSS class>
 */
function get_gravity_forms_with_css_class( $css_class ) {
	return array_reduce( GFAPI::get_forms(), function( $forms_with_css_class, $form ) use ( $css_class ) {
		$fields_with_class = get_gravity_form_fields_with_css_class( $form, $css_class );

		if ( $fields_with_class ) {
			$forms_with_css_class[ "{$form['id']} - {$form['title']}" ] = $fields_with_class;
		}

		return $forms_with_css_class;
	}, [] );
}

/**
 * Get all fields in a Gravity Form that have a CSS class.
 *
 * @param  array  $form      The Gravity Form data.
 * @param  string $css_class The CSS class to search for.
 *
 * @return array  Fields that have the CSS class or empty array if none.
 */
function get_gravity_form_fields_with_css_class( $form, $css_class ) {
	return array_filter( $form['fields'], function( $field ) use ( $css_class ) {
		return in_array( $css_class, explode( ' ', $field->cssClass ), true );
	} );
}