Newt Scamander had a black and yellow Hufflepuff scarf in his suitcase when it was checked by harbor Customs in 1926 New York City. It appeared with other common items in his suitcase instead of his menagerie of Fantastic Beasts when he turned a small dial to “Muggle Worthy” (WFT).
The mention of a Hufflepuff scarf in the Fantastic Beasts script book is the very first canon mention of a House Scarf. Of course they are a common prop in the Harry Potter movies but have never been mentioned by the author in written canon before now.
In a tweet from 2015, J.K. Rowling said that Newt ushered in the "Dawn of the Age of Hufflepuff"
— J.K. Rowling (@jk_rowling) September 9, 2015