Don't let the Pigeon Drive the Bus (partially found drafts of children's picture book; 1997-2003)
Don't Let the Pigeon Drive The Bus is a children's book published in 2003 by Mo Willems about a Pigeon that wants to drive a bus, so a bus driver had to leave and asked the reader to not allow the Pigeon to drive the bus. Before the book was released, Mo Willems was drawing on a sketchbook 10 years before the book's release, The Pigeon was created in 1997, and some drafts have been created for Don't Let the Pigeon Drive the Bus with dates from 1997 to 2003.
This is the earliest draft we know of the book, Its year of creation is unknown but it's probably 1997 or 1998. The back cover also contains the red question mark-shaped 'P' from the Curious Pictures logo.
After The Pigeon was created in a general 1997 sketchbook, One of the first drafts have been created, known as the 1998 version of Don't Let the Pigeon Drive The Bus Sketchbook. The sketchbook was longer then the final version, but it still had some pages that survived in the final version.
After the 1998 sketchbook, a sketch was created in 1999, and added color. You can see a difference in The Pigeon's design at that time, as he originally had an orange collar instead of white one.
3 years after the 1999 sketch, Mo Willems created a "late-2001-2002" version of Don't Let the Pigeon Drive the Bus. This version was closer to the final one.
This is believed to be a 2002-2003 version because of how close it is to the final version. The speech bubbles have different colors.
Some pages of the drafts has been surfaced online at the Amazon listing of Don't Let the Pigeon Drive the Bus.
In 2013, A book Called Don't Pigeonhole Me was published and it contained stuff from the Don't Let the Pigeon Drive the Bus Drafts.
In 2016, The Art and Whimsy of Mo Willems Exhibit opened, and it shows some stuff from the drafts. There's also videos of the exhibit which show more stuff from the Don't Let the Pigeon Drive the Bus Drafts. 
In 2020, Mo Willems posted the first episode of Lunch Doodles, an educational show made for Kennedy Center Education Artist-in-Residence at Home during COVID-19 lockdown. In that episodes, Mo Willems showed some stuff from the drafts while revealing other drafts in this episode.