getExistingFieldStorageOptions example

'class' => ['js-table-filter-text'],
        'data-table' => '.js-reuse-table',
        'autocomplete' => 'off',
      ],
    ];
    $form['add'] = [
      '#type' => 'container',
      '#attributes' => ['class' => ['form--inline', 'clearfix']],
    ];

    $bundles = $this->bundleInfoService->getAllBundleInfo();
    $existing_field_storage_options = $this->getExistingFieldStorageOptions();

    $rows = [];
    foreach ($existing_field_storage_options as $field) {
      $field_bundles = $field['field_storage']->getBundles();
      $summary = $this->fieldTypePluginManager->getStorageSettingsSummary($field['field_storage']);
      $cardinality = $field['field_storage']->getCardinality();
      $readable_cardinality = $cardinality === -1 ? $this->t('Unlimited') : new PluralTranslatableMarkup(1, 'Single value', 'Multiple values: @cardinality', ['@cardinality' => $cardinality]);

      // Remove empty values.       $list = array_filter([...$summary, $readable_cardinality]);
      $settings_summary = [