A few buildings in the game are called "Helper" buildings. These buildings will give you one needed item along with their usual profits.

How do these buildings work:

1) items drop RANDOMLY from these buildings;

2) you can't receive from these buildings:
- Items needed for the crafts in production buildings, for example - Pillow for the production of the Sofas at the Furniture Factory;

- Items that you need to ask friends for;

- items that are produced in quests (for example, as in Lemonade factory quest);

3) you can receive from buildings:

- Items required in active quests, including quests with random tasks;

- Items for decors in the Academy of Magic;

- +3 energy, if you do not need items in active quests or for the Academy;
 
The current list of Helper buildings in Supercity:
  1. Romantic date
  2. Tree house
  3. Dracula's Castle
  4. Neuschwanstein Castle
  5. Art Gallery
  6. The Emir’s Palace
  7. Indian Palace
  8. Santa's sleigh
  9. Rabbit meadow
  10. Omnibus depot
  11. Train Robbery 
  12. Yacht transportation
  13. Statue of Maat 
  14. Agronomist laboratory 
  15. Mad Tea Party
  16. Chariot Workshop
  17. Elf Houses
  18. Mysterious Castle
  19. Indian market
  20. Dinner Date
  21. Holiday “Find all Eggs” 
  22. Kite Workshop
  23. Residence of Harmony
  24. Reserve security
  25. Warning Bell (Obtained only by activating notifications on the portal. You can collect profits ONLY from the portal)
  26. Mayan Temple archeological dig
  27. Town meeting hall
  28. Seafarer’s Haven 
  29. Drakkar Restoration
  30. Bonsai studio 
  31. Cloud-high Resort
  32. Haunted hippodrome
  33. Tolek construction
  34. Christmas clock tower
  35. "Penguinarium" Research Center
  36. Tsar’s Residence 
  37. Maiden’s Tower
  38. Sculptor's studio
  39. Japanese gardens
  40. Easter Aerodrome
  41. Florists's house
  42. Solomon's Temple Excavation
  43. Citadel of Seekers
  44. 'Guitar Riff' Radio Station
  45. Changdeokgung Palace
  46. “Board´em!” ride
  47. Sultan's Palace
  48. Broomstick Race   
  49. Harvest in the Tropics 
  50. Christmas Depot
  51. City Herbalist's Houses
  52. Factory of Extraordinary Fragrances
  53. Druid Village
  54. Easter Party
  55. Luxurious Palace
  56. Georgian Fortress
  57. Northern Spa Center
  58. Dollmaker's Workshop
  59. Han’s Palace
  60. Caramel Garden
  61. Labyrinth in the field
  62. Catnip Farm
  63. Clock Foundry
  64. Sami Village
  65. Rock Festival Stage
  66. Sky Garden
  67. Moonlight Pavilion
  68. Decoration Workshop
  69. Hopping Bunnies Carousel
  70. Maramureș church
  71. Dodo's house
  72. Dragon's Nest
  73. Temple of Nike
  74. Tibetan Palace
  75. Wonderful Bazaar
  76. Merry Cowboy Saloon
  77. Serbian Church
  78. Tropical Garden
  79. Magic Grove
  80. Armenian Cathedral
  81. Phantom Dock
  82. Steps Campsite
  83. Orange-Processing Shop
  84. Toy Warehouse