Moodle - Built-in blocks

They are built-in blocks of Moodle:

mdl_block;

+----+
| id   | name 
+----+
|  1 | activity_modules 
|  2 | admin_bookmarks
|  3 | badges
|  4 | blog_menu
|  5 | blog_recent
|  6 | blog_tags
|  7 | calendar_month
|  8 | calendar_upcoming
|  9 | comments
| 10 | community
| 11 | completionstatus
| 12 | course_list
| 13 | course_overview
| 14 | course_summary
| 15 | feedback 
| 16 | glossary_random 
| 17 | html 
| 18 | login             
| 19 | mentees           
| 20 | messages          
| 21 | mnet_hosts        
| 22 | myprofile         
| 23 | navigation        
| 24 | news_items        
| 25 | online_users      
| 26 | participants      
| 27 | private_files     
| 28 | quiz_results      
| 29 | recent_activity   
| 30 | rss_client        
| 31 | search_forums     
| 32 | section_links     
| 33 | selfcompletion    
| 34 | settings          
| 35 | site_main_menu    
| 36 | social_activities 
| 37 | tag_flickr        
| 38 | tag_youtube       
| 39 | tags