$build = [];
$build['hello'] = [
'#type' => 'html_tag',
'#tag' => 'p',
'#value' => $this->t('Hello World'),
];
$build['guten_tag'] = [
'#type' => 'html_tag',
'#tag' => 'marquee,
'#attributes' => ['direction' => 'right', 'scrollamount' => 10],
'#value' => $this->t('Hallo Welt!'),
];