...
class TickerCollection(ormar.Model):
  class Meta(BaseMeta):
    tablename = "ticker_collection"

  id: int = ormar.Integer(name="ticker_collection_id", nullable=False, primary_key=True, autoincrement=True)

  createdByUser: Optional[User] = ormar.ForeignKey(User, name="created_by_user_id", nullable=True, unique=False)
  isPublic: bool                = ormar.Boolean(         name="is_public",          nullable=False, default=False)
  name: str                     = ormar.Text(            name="name",               nullable=False)
  description: str              = ormar.Text(            name="description",        nullable=True)
  tickers: Optional[List[Ticker]] = ormar.ManyToMany(
    to=Ticker,
    through=TickerToTickerCollection,
    related_name="tickerCollections",
    through_relation_name="ticker_collection_id",
    through_reverse_relation_name="ticker_id",
    # is_through_relation_column_nullable=False,
    # is_through_reverse_relation_column_nullable=False,
  )
...

...
op.create_table('ticker_to_ticker_collection',
    sa.Column('id', sa.Integer(), nullable=False),
    sa.Column('ticker_id', sa.Integer(), nullable=True),
    sa.Column('ticker_collection_id', sa.Integer(), nullable=True),
    sa.ForeignKeyConstraint(['ticker_collection_id'], ['ticker_collection.ticker_collection_id'], name='asd1', onupdate='CASCADE', ondelete='CASCADE'),
    sa.ForeignKeyConstraint(['ticker_id'], ['ticker.ticker_id'], name='asd2', onupdate='CASCADE', ondelete='CASCADE'),
    sa.PrimaryKeyConstraint('id')
    )
...