Some of the new village structures will never generate in your world because they are missing a jigsaw block.

The structures include:

• For the plains village:
  • minecraft:village/plains/houses/plains_tool_smith_1

• For the snowy village:
  • minecraft:village/snowy/houses/snowy_medium_house_1
  • minecraft:village/snowy/houses/snowy_medium_house_2
  • minecraft:village/snowy/houses/snowy_small_house_2
  • minecraft:village/snowy/houses/snowy_small_house_5
  • minecraft:village/snowy/houses/snowy_tannery_1
  • minecraft:village/snowy/houses/snowy_masons_house_2

• For the savanna village:
  • minecraft:village/savanna/savanna_lamp_post_01
  • minecraft:village/savanna/houses/savanna_small_house_8
  • minecraft:village/savanna/houses/savanna_weaponsmith_2
  • minecraft:village/savanna/houses/savanna_mason_1

• For desert village: 
  • minecraft:village/desert/houses/desert_farm_2
  • minecraft:village/desert/houses/desert_small_house_8
  • minecraft:village/desert/houses/desert_blacksmith_1

• For taiga village:
  • minecraft:village/taiga/taiga_decoration_1
  • minecraft:village/taiga/houses/taiga_armorer_house_2
    this one got .../taiga_armorer_2 as replacement as of 19w04a (the old structure file still exists however)
  • minecraft:village/taiga/houses/taiga_cartographer_house_1
• For the zombie desert village:
  • minecraft:village/desert/zombie/houses/desert_small_house_8
• For the zombie taiga village:
  • minecraft:village/taiga/zombie/houses/taiga_armorer_house_2

You can find those structures in these worlds made by slicedlime:

• 18w49a
• 18w50a
• 19w04a
  (links are in the description of the video)