Look in the quilting forum. The ladies there have lots of helpful info.

I'v never seen a pattern but I have seen a crayon caddy that looked like it would be easy to make. You might can do a google search.
Susan

Hi lynnlynn...these are the crayon bags I made for my grandson's for Easter. I did not use a pattern, and they are quilted, but they are easy to make from plain fabric, or pre quilted fabric.

I used fat quarters(18x22 inch pre-cut fabrics)...so if you purchase regular fabric you will need about 1/4 of a yard for the body (does not include lining if you use it.)
You will also need about 1/4 yard of coordinating fabric for the crayon pockets and the handles. (if the fabric looks crooked on the bolt, I'd buy 1/2 yard to be sure I had enough!)

This is basically how I did it.
I laid my fabric right sides together, so you have 2 layers. I laid the coloring book on top of it and drew around it..being sure to leave at least a couple of inches at the top. Remove the book and draw another line 1" away from your book drawing line on the sides and bottom. Add 3" to the book drawing line at the top. Cut out your bag.

For the crayon pockets, I cut the fabric to fit across the bag. For the height, I measured the fabric so that the point of the crayon stuck out, added a 1/4" inch for a pressed up hem at the bottom and added 1/2" at the top so I could turn it under 1/4", press, turn down again 1/4" ,then I sewed this top hem.

Lay the hemmed pocket on the bag where you want it, pin, and sew across the bottom of the pocket to attach to bag. I then sewed the lines to make each pocket...I used big crayons and made my pockets 1 1/2 wide. (One inch wide pockets were too tight for little hands to insert the crayons).

I then cut the coordinating fabric into 3 inch strips for the handles, the length I wanted. I pressed 1/4 fold on one long edge, then folded the raw edged fabric into the middle, folded the side with the 1/4 seam over it and stitched in place to cover raw seam.

I then pressed down 1/4 inch on the top of each bag top, then folded edge in 1" and sewed down. I then attached the handles to the bag front and back. Finally, I sewed the bag together on the 3 sides. (the pockets get sewed into the side seams.)
You can add as many pockets as you like. I used 1 pocket panels on each side of the bag.

I couldn't find a free pattern online, only ones you could purchase.
Hope this helped. (you can click on the pictures for a larger view.)
Woodsy