gform_column_input_content.php

<?php

// Format: gform_column_input_content_FORMID_FIELDID_COLUMN.
add_filter( 'gform_column_input_content_3_1_4', 'pbj_crust_option', 10, 6 );
function pbj_crust_option( $input, $input_info, $field, $text, $value, $form_id ) {

	// Field name needs to match List field syntax.
	$field_name = 'input_' . $field->id . '[]';

	// We want tabindex for keyboard accessibility.
	$tabindex = GFCommon::get_tabindex();

	// Build the HTML output.
	$new_input = '<input type="checkbox" name="' . $field_name . '" ' . $tabindex . '"/>';

	return $new_input;
}

list-field-filter.php

<?php

// Format: gform_column_input_FORMID_FIELDID_COLUMN.
add_filter( 'gform_column_input_3_1_2', 'pbj_pb_selections' );
function pbj_pb_selections() {

	$pb_types = array(
		'type'    => 'select',
		'choices' => array( 'Cashew Butter', 'Peanut Butter', 'Sun Butter' ),
	);

	return $pb_types;

}

// Format: gform_column_input_FORMID_FIELDID_COLUMN.
add_filter( 'gform_column_input_3_1_3', 'pbj_jelly_selections' );
function pbj_jelly_selections() {

	$jelly_flavors = array(
		'type'    => 'select',
		'choices' => array( 'Grape', 'Strawberry', 'Raspberry' ),
	);

	return $jelly_flavors;

}

sandwich-repeater.php

<?php

// Replace 4 with your FORM ID.
add_filter( 'gform_form_post_get_meta_4', 'sandwich_creations_repeater' );
function sandwich_creations_repeater( $form ) {

	// Create a Single Line text field for the sandwich name.
	$sandwich_name = GF_Fields::create(
		array(
			'type'   => 'text',
			'id'     => 1003, // The Field ID must be unique on the form.
			'formId' => $form['id'],
			'label'  => 'Sandwich',
		)
	);

	// Create a textarea field for the sandwich description.
	$sandwich_description = GF_Fields::create(
		array(
			'type'   => 'textarea',
			'id'     => 1002, // The Field ID must be unique on the form
			'formId' => $form['id'],
			'label'  => 'Description',
			'size'   => 'small',
		)
	);

	// Create an email field for the team member's email address
	$sandwich_type = GF_Fields::create(
		array(
			'type'    => 'radio',
			'id'      => 1001, // The Field ID must be unique on the form
			'formId'  => $form['id'],
			'label'   => 'Sandwich type',
			'choices' => array(
				array(
					'text' => 'Carnivore',
				),
				array(
					'text' => 'Vegetarian',
				),
			),
		)
	);

	// Create a repeater for the sandwiches and add the newly created fields to display inside the repeater.
	$sandwich_repeater = GF_Fields::create(
		array(
			'type'          => 'repeater',
			'id'            => 1000, // The Field ID must be unique on the form
			'formId'        => $form['id'],
			'label'         => 'Sandwiches',
			'addButtonText' => 'Add another sandwich', // Optional
			'fields'        => array( $sandwich_name, $sandwich_description, $sandwich_type ), // Add the fields here.
		)
	);

	$form['fields'][] = $sandwich_repeater;

	return $form;
}

time-tracking-nested-repeater.php

<?php

// Replace 5 with your FORM ID.
add_filter( 'gform_form_post_get_meta_5', 'time_tracking_repeater' );
function time_tracking_repeater( $form ) {

	$task_name = GF_Fields::create(
		array(
			'type'   => 'text',
			'id'     => 1000,
			'formId' => $form['id'],
			'label'  => 'Task',
		)
	);

	$task_description = GF_Fields::create(
		array(
			'type'   => 'textarea',
			'id'     => 1001,
			'formId' => $form['id'],
			'label'  => 'Description',
			'size'   => 'small',
		)
	);

	$date = GF_Fields::create(
		array(
			'type'   => 'date',
			'id'     => 1002,
			'formId' => $form['id'],
			'label'  => 'Date',
			'size'   => 'small',
		)
	);

	$start_time = GF_Fields::create(
		array(
			'type'   => 'time',
			'id'     => 1003,
			'formId' => $form['id'],
			'label'  => 'Start Time',
			'size'   => 'small',
		)
	);

	$end_time = GF_Fields::create(
		array(
			'type'   => 'time',
			'id'     => 1004,
			'formId' => $form['id'],
			'label'  => 'End Time',
			'size'   => 'small',
		)
	);

	$nested_repeater = GF_Fields::create(
		array(
			'type'          => 'repeater',
			'id'            => 1005, // The Field ID must be unique on the form
			'formId'        => $form['id'],
			'label'         => 'Time Entry',
			'addButtonText' => 'Add another time entry',
			'fields'        => array( $date, $start_time, $end_time ),
		)
	);

	$task_repeater = GF_Fields::create(
		array(
			'type'          => 'repeater',
			'id'            => 1006, // The Field ID must be unique on the form
			'formId'        => $form['id'],
			'label'         => 'Tasks',
			'addButtonText' => 'Add another task',
			'fields'        => array( $task_name, $task_description, $nested_repeater ),
		)
	);

	$form['fields'][] = $task_repeater;

	return $form;
}