// указываем название TV
$dropdownValues = $modx->resource->getTVValue('dropdown_tv');

$valuesArray = explode(',', $dropdownValues);

// оберачиаем значения в теги "option"
foreach ($valuesArray as $value) {
    echo '<option>' . trim($value) . '</option>';
}

$client = new GuzzleHttp\Client();
$res = $client->request('GET', 'https://api.site', [
    'headers' => [
        'Content-Type' => 'application/json',
        'Authorization' => 'OAuth НАШ TOKEN'
    ]
]);
$res->getStatusCode();

$html = $res->getBody();

echo $html;

{20 | locfield : 'migx_why_us_list'}

'processTVs' => '1'

foreach ($resources as $id) {
				    
				    $remains = $this->modx->getCollection('msprRemains', array('product_id' => $id));
                	$remainsResult = array();
                	foreach ($remains as $remain) {
						$options = $remain->get('options');
                		$remainsResult[$options['size']] = array(
                			'id'      => $remain->get('id'),
                			'remains' => (int) $remain->get('remains')
                		);
                	}
				    
					if (isset($tmp[$id])) {
						if ( $remainsResult[$value]['remains'] > 0 ) {
							$matched[] = $id;
						}
					}
				}