Determine what blocks are used in a Wagtail StreamField.

block_types_used_in_field.py

def block_types_used_in_field(queryset, field_name: str) -> set:
    used_block_types = set()
    for page in queryset: 
        for block in getattr(page, field_name):
            used_block_types.add(block.block_type)
    return used_block_types
  
  
# block_types_used_in_field(BlogPage.objects.all(), 'body')