diff --git a/config/install/monitoring.sensor_config.user_failed_logins.yml b/config/install/monitoring.sensor_config.user_failed_logins.yml
index 51dc3d3..cd537af 100644
--- a/config/install/monitoring.sensor_config.user_failed_logins.yml
+++ b/config/install/monitoring.sensor_config.user_failed_logins.yml
@@ -2,7 +2,7 @@ id: user_failed_logins
 label: 'Failed user logins'
 description: 'Failed user logins by Watchdog'
 category: 'User activity'
-plugin_id: user_failed_logins
+plugin_id: watchdog_aggregator
 value_type: 'number'
 value_label: 'Login attempts'
 status: TRUE
diff --git a/config/install/monitoring.sensor_config.user_sessions_logouts.yml b/config/install/monitoring.sensor_config.user_sessions_logouts.yml
index 7141ca3..75d4a86 100644
--- a/config/install/monitoring.sensor_config.user_sessions_logouts.yml
+++ b/config/install/monitoring.sensor_config.user_sessions_logouts.yml
@@ -2,7 +2,7 @@ id: user_session_logouts
 label: 'User session logouts'
 description: 'User session logouts by Watchdog'
 category: 'User activity'
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 value_type: 'number'
 value_label: 'Logouts'
 status: TRUE
diff --git a/config/install/monitoring.sensor_config.user_successful_logins.yml b/config/install/monitoring.sensor_config.user_successful_logins.yml
index 7fa49b3..dccaaea 100644
--- a/config/install/monitoring.sensor_config.user_successful_logins.yml
+++ b/config/install/monitoring.sensor_config.user_successful_logins.yml
@@ -2,7 +2,7 @@ id: user_successful_logins
 label: 'Successful user logins'
 description: 'Successful user logins by Watchdog'
 category: 'User activity'
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 value_type : 'number'
 value_label: 'Login attempts'
 status: TRUE
diff --git a/config/optional/monitoring.sensor_config.dblog_404.yml b/config/optional/monitoring.sensor_config.dblog_404.yml
index ded9ebb..2ebc5d0 100644
--- a/config/optional/monitoring.sensor_config.dblog_404.yml
+++ b/config/optional/monitoring.sensor_config.dblog_404.yml
@@ -7,7 +7,7 @@ id: dblog_404
 label: 'Page not found errors'
 description: 'Page not found errors logged by watchdog'
 category: Watchdog
-plugin_id: dblog_404
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: 'Watchdog events'
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_alert.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_alert.yml
index b859479..08238e5 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_alert.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_alert.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_alert
 label: 'Severity Alert'
 description: 'Watchdog entries of severity Alert'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_critical.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_critical.yml
index e8e7c12..c094ce5 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_critical.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_critical.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_critical
 label: 'Severity Critical'
 description: 'Watchdog entries of severity Critical'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_debug.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_debug.yml
index ddd18a6..d567a5e 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_debug.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_debug.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_debug
 label: 'Severity Debug'
 description: 'Watchdog entries of severity Debug'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_emergency.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_emergency.yml
index 54e3229..bb1820b 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_emergency.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_emergency.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_emergency
 label: 'Severity Emergency'
 description: 'Watchdog entries of severity Emergency'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_error.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_error.yml
index 7a034b7..731e15d 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_error.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_error.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_error
 label: 'Severity Error'
 description: 'Watchdog entries of severity Error'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_info.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_info.yml
index eb134c3..5e50f45 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_info.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_info.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_info
 label: 'Severity Info'
 description: 'Watchdog entries of severity Info'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_notice.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_notice.yml
index c62e079..6d99f1e 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_notice.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_notice.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_notice
 label: 'Severity Notice'
 description: 'Watchdog entries of severity Notice'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_event_severity_warning.yml b/config/optional/monitoring.sensor_config.dblog_event_severity_warning.yml
index 21b35df..6f090c5 100644
--- a/config/optional/monitoring.sensor_config.dblog_event_severity_warning.yml
+++ b/config/optional/monitoring.sensor_config.dblog_event_severity_warning.yml
@@ -7,7 +7,7 @@ id: dblog_event_severity_warning
 label: 'Severity Warning'
 description: 'Watchdog entries of severity Warning'
 category: Watchdog
-plugin_id: database_aggregator
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: Events
 value_type: number
diff --git a/config/optional/monitoring.sensor_config.dblog_image_missing_style.yml b/config/optional/monitoring.sensor_config.dblog_image_missing_style.yml
index 55a9eb3..a747a29 100644
--- a/config/optional/monitoring.sensor_config.dblog_image_missing_style.yml
+++ b/config/optional/monitoring.sensor_config.dblog_image_missing_style.yml
@@ -8,7 +8,7 @@ id: dblog_image_missing_style
 label: 'Image derivative creation fail'
 description: 'Image derivative creation fails'
 category: Watchdog
-plugin_id: image_style_missing
+plugin_id: watchdog_aggregator
 result_class: null
 value_label: 'Watchdog entries'
 value_type: number
diff --git a/config/schema/monitoring.schema.yml b/config/schema/monitoring.schema.yml
index 7398eef..c5e96af 100644
--- a/config/schema/monitoring.schema.yml
+++ b/config/schema/monitoring.schema.yml
@@ -187,22 +187,14 @@ monitoring.settings.search_api_unindexed:
       type: string
       label: 'Index ID'
 
-monitoring.settings.dblog_404:
+monitoring.settings.watchdog_aggregator:
   type: monitoring.settings.database_aggregator
-  label: '404 settings'
-
-monitoring.settings.image_style_missing:
-  type: monitoring.settings.database_aggregator
-  label: 'Missing images sensor settings'
+  label: 'Watchdog sensor settings'
 
 monitoring.settings.user_integrity:
   type: monitoring.settings_base
   label: 'Privileged user integrity'
 
-monitoring.settings.user_failed_logins:
-  type: monitoring.settings.database_aggregator
-  label: 'Failed user sensor settings'
-
 monitoring.settings.twig_debug_mode:
   type: monitoring.settings_base
   label: 'Monitor twig settings'
diff --git a/src/Plugin/monitoring/SensorPlugin/Dblog404SensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/Dblog404SensorPlugin.php
deleted file mode 100644
index daed921..0000000
--- a/src/Plugin/monitoring/SensorPlugin/Dblog404SensorPlugin.php
+++ /dev/null
@@ -1,48 +0,0 @@
-<?php
-/**
- * @file
- * Contains \Drupal\monitoring\Plugin\monitoring\SensorPlugin\Dblog404SensorPlugin.
- */
-
-namespace Drupal\monitoring\Plugin\monitoring\SensorPlugin;
-
-use Drupal\monitoring\Result\SensorResultInterface;
-
-/**
- * Monitors 404 page errors from dblog.
- *
- * @SensorPlugin(
- *   id = "dblog_404",
- *   provider = "dblog",
- *   label = @Translation("404 page errors (database log)"),
- *   description = @Translation("Monitors 404 page errors from database log."),
- *   addable = FALSE
- * )
- *
- * Displays URL with highest occurrence as message.
- */
-class Dblog404SensorPlugin extends DatabaseAggregatorSensorPlugin {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getAggregateQuery() {
-    $query = parent::getAggregateQuery();
-    $query->addField('watchdog', 'message');
-    // The message is the requested 404 URL.
-    $query->groupBy('message');
-    $query->orderBy('records_count', 'DESC');
-    $query->range(0, 1);
-    return $query;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function runSensor(SensorResultInterface $result) {
-    parent::runSensor($result);
-    if (!empty($this->fetchedObject) && !empty($this->fetchedObject->message)) {
-      $result->addStatusMessage($this->fetchedObject->message);
-    }
-  }
-}
diff --git a/src/Plugin/monitoring/SensorPlugin/ImageMissingStyleSensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/ImageMissingStyleSensorPlugin.php
deleted file mode 100644
index f952053..0000000
--- a/src/Plugin/monitoring/SensorPlugin/ImageMissingStyleSensorPlugin.php
+++ /dev/null
@@ -1,101 +0,0 @@
-<?php
-/**
- * @file
- * Contains \Drupal\monitoring\Plugin\monitoring\SensorPlugin\ImageMissingStyleSensorPlugin.
- */
-
-namespace Drupal\monitoring\Plugin\monitoring\SensorPlugin;
-
-use Drupal\monitoring\Result\SensorResultInterface;
-use Drupal;
-
-/**
- * Monitors image derivate creation errors from dblog.
- *
- * @SensorPlugin(
- *   id = "image_style_missing",
- *   label = @Translation("Image Missing Style"),
- *   description = @Translation("Monitors image derivate creation errors from database log."),
- *   provider = "image",
- *   addable = FALSE
- * ),
- *
- * Displays image derivate with highest occurrence as message.
- */
-class ImageMissingStyleSensorPlugin extends DatabaseAggregatorSensorPlugin {
-
-  /**
-   * The path of the most failed image.
-   *
-   * @var string
-   */
-  protected $sourceImagePath;
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getAggregateQuery() {
-    // Extends the watchdog query.
-    $query = parent::getAggregateQuery();
-    $query->addField('watchdog', 'variables');
-    $query->groupBy('variables');
-    $query->orderBy('records_count', 'DESC');
-    return $query;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function runSensor(SensorResultInterface $result) {
-    parent::runSensor($result);
-    if (!empty($this->fetchedObject)) {
-      $variables = unserialize($this->fetchedObject->variables);
-      if (isset($variables['%source_image_path'])) {
-        $result->addStatusMessage($variables['%source_image_path']);
-        $this->sourceImagePath = $variables['%source_image_path'];
-      }
-    }
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function resultVerbose(SensorResultInterface $result) {
-    $output = parent::resultVerbose($result);
-
-    // If non found, no reason to query file_managed table.
-    if ($result->getValue() == 0) {
-      return $output;
-    }
-
-    // In case we were not able to retrieve this info from the watchdog
-    // variables.
-    if (empty($this->sourceImagePath)) {
-      $message = t('Source image path is empty, cannot query file_managed table');
-    }
-    else {
-      $query_result = \Drupal::entityQuery('file')
-        ->condition('uri', $this->sourceImagePath)
-        ->execute();
-    }
-
-    if (!empty($query_result)) {
-      $file = file_load(array_shift($query_result));
-      /** @var \Drupal\file\FileUsage\FileUsageInterface $usage */
-      $usage = \Drupal::service('file.usage');
-      $message = t('File managed records: <pre>@file_managed</pre>', array('@file_managed' => var_export($usage->listUsage($file), TRUE)));
-    }
-
-    if (empty($message)) {
-      $message = t('File @file record not found in the file_managed table.', array('@file' => $result->getMessage()));
-    }
-
-    $output['message'] = array(
-      '#type' => 'item',
-      '#title' => t('Message'),
-      '#markup' => $message,
-    );
-
-    return $output;
-  }
-}
diff --git a/src/Plugin/monitoring/SensorPlugin/UserFailedLoginsSensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/UserFailedLoginsSensorPlugin.php
deleted file mode 100644
index 3e550d5..0000000
--- a/src/Plugin/monitoring/SensorPlugin/UserFailedLoginsSensorPlugin.php
+++ /dev/null
@@ -1,49 +0,0 @@
-<?php
-/**
- * @file
- * Contains \Drupal\monitoring\Plugin\monitoring\SensorPlugin\UserFailedLoginsSensorPlugin.
- */
-
-namespace Drupal\monitoring\Plugin\monitoring\SensorPlugin;
-
-use Drupal\monitoring\Result\SensorResultInterface;
-
-/**
- * Monitors user failed login from dblog messages.
- *
- * @SensorPlugin(
- *   id = "user_failed_logins",
- *   label = @Translation("User Failed Logins"),
- *   description = @Translation("Monitors user failed login from dblog messages."),
- *   addable = FALSE
- * )
- *
- * Helps to identify bots or brute force attacks.
- */
-class UserFailedLoginsSensorPlugin extends DatabaseAggregatorSensorPlugin {
-
-  /**
-   * {@inheritdoc}
-   */
-  public function getAggregateQuery() {
-    $query = parent::getAggregateQuery();
-    $query->addField('watchdog', 'variables');
-    $query->groupBy('watchdog.variables');
-    return $query;
-  }
-
-  /**
-   * {@inheritdoc}
-   */
-  public function runSensor(SensorResultInterface $result) {
-    $records_count = 0;
-    foreach ($this->getAggregateQuery()->execute() as $row) {
-      $records_count += $row->records_count;
-      $variables = unserialize($row->variables);
-      $result->addStatusMessage('@user: @count', array('@user' => $variables['%user'], '@count' => $row->records_count));
-    }
-
-    $result->setValue($records_count);
-  }
-
-}
diff --git a/src/Plugin/monitoring/SensorPlugin/WatchdogAggregatorSensorPlugin.php b/src/Plugin/monitoring/SensorPlugin/WatchdogAggregatorSensorPlugin.php
index 2a995d1..99d9276 100644
--- a/src/Plugin/monitoring/SensorPlugin/WatchdogAggregatorSensorPlugin.php
+++ b/src/Plugin/monitoring/SensorPlugin/WatchdogAggregatorSensorPlugin.php
@@ -77,6 +77,7 @@ class WatchdogAggregatorSensorPlugin extends DatabaseAggregatorSensorPlugin impl
   public function buildConfigurationForm(array $form, FormStateInterface $form_state) {
     $form = parent::buildConfigurationForm($form, $form_state);
     $form['#title'] = t('Watchdog Sensor plugin settings');
+    // The following fields should not be edited, so we disable them.
     $form['table']['#disabled'] = TRUE;
     $form['aggregation']['time_interval_field']['#disabled'] = TRUE;
     return $form;
diff --git a/src/Tests/MonitoringCoreWebTest.php b/src/Tests/MonitoringCoreWebTest.php
index 562db7f..328cf2d 100644
--- a/src/Tests/MonitoringCoreWebTest.php
+++ b/src/Tests/MonitoringCoreWebTest.php
@@ -63,7 +63,7 @@ class MonitoringCoreWebTest extends MonitoringTestBase {
     $this->assertTrue(count($results) == 3, '3 fields have been found in the verbose result.');
     // The username should be replaced in the message.
     $this->drupalGet('/admin/reports/monitoring/sensors/dblog_event_severity_notice');
-    $this->assertText('Session opened for %name');
+    $this->assertText('Session opened for' . $test_user->label());
     // 'No results' text is displayed when the query has 0 results.
     $this->drupalGet('/admin/reports/monitoring/sensors/dblog_event_severity_warning');
     $this->assertText('No results were found in the table.');