Here is a Horse Show Checklist for the "Non-Owner".
I just know that whenever I was trying to get checklists for shows, they would always have extra stuff about trailers and horse supplies like feed, trailer blocks, etc. Well, I don't own my own horse, so I didn't need that stuff on my list. So I made one! :] Just thought I'd share it. It has spaces to add your own stuff too.
You can just save it and print it out, put it on your tack rooms wall, etc. :]
The image is attached so you can see it before you click the link.