First, do you have a manual for the tractor? Many times the manual will have pictures of the warning labels. If so, take those pictures to most sign shops where they will scan them and produce exact vinyl copies that are peel and press.
If generic in nature, most any tractor manual will do.
You might not want to find them. I called a Bomford dealer for a new decal for my control lever box (old one was faded to a white rectangle). They had it...for $63...YMMV, but a Sharpie worked for me!
Have you considered a inexpensive labeler? I have one, bought it at staples. It came with uv-resistant exterior label tape.
This is the one I have:Staples.com®. that was easy®.