Form api does not have any Reset button

Also does not have reset input

See https://www.w3schools.com/tags/att_input_type_reset.asp

Until this is fixed, as a workaround you can use two approaches for now:
1. Use the form redirect like this:

  public function buildForm(array $form, FormStateInterface $form_state) {
    ...    
    $form['input_data']['options']['clear'] = [
      '#type' => 'input',
      '#value' => $this->t('Reset'),
      '#limit_validation_errors' => [],
      '#submit' => [[$this, 'resetForm']],
    ];
    return $form;
  }
  public function resetForm(array &$form, FormStateInterface $form_state): void {
    // A workaround for the issue
    // https://www.drupal.org/project/drupal/issues/2799269
    $form_state->setRedirect('<current>');
  }

2. Use the browser API to reset the form:

$form['reset'] = [
      '#type' => 'input',
      '#value' => $this->t('Reset'),
      '#limit_validation_errors' => [],
      '#attributes' => [
        'onclick' => 'this.form.reset(); return false;',
      ];
    );

But the proper API from Drupal Core would be much better, so keeping the issue as active.