One of the Gravity Falls Journals was seen in the Amphibia episode “Trip to the Archives” I'm sure this has been pointed out already but I just wanted to post about it :
Gravity Falls - Journal 3 replica (with complete pages) | RPF Costume and Prop Maker Community
Gravity Falls Journal 1-2 Unofficial Big Size English Hard - Etsy UK
Gravity Falls Journal 3 Unofficial 20x27 Cm English - Etsy UK
Gravity Falls Journal 1: Gravity Falls Prop Book Journal | Gravity Falls Journal 1 2 3 Fan Edition Diary | Back To School Notebook: Amazon.co.uk: Marline: 9798488781368: Books
Journal 1 | Gravity Falls Wiki | Fandom
Gravity Falls: Journal 3 / Nightmare Fuel - TV Tropes
Creating My Own Gravity Falls Journal! - YouTube
Gravity Falls: Journal 3 by Alex Hirsch, Rob Renzetti, Stephanie Ramirez, Andy Gonsalves, Hardcover | Barnes & Noble®
Alex Hirsch Talks Gravity Falls and the Fascinating Journal 3 Project - Paste
Disney Гравити Фолз: Дневник 3 GRAVITY FALLS: JOURNAL 3 Russian Language Book 9785699906567 | eBay
Gravity Falls Journal 1: Gravity Falls Prop Book Journal | Gravity Falls Journal 1 2 3 Fan Edition Diary | Back To School Notebook: Amazon.co.uk: Luz Kiddies Press: 9798483795568: Books
Gravity Falls Journal 3 – Extra Pages | The Elder Props
Gravity Falls Journal 4: Gravity Falls Fan Made Prop Book Journal | Gravity Falls Journal 1 2 3 diary | Hardcover Edition.: Amazon.co.uk: Press, Proop Kings: 9798483913399: Books