I needed a simple 4.25x6.25 envelope template, because I'd like to start making my very own envelopes for my Etsy products. Anyway, after several hours of searching the internet, I decided to make my own. I'm very pleased with the way it turned out.
You can get it for free!
The entire thing was made in Adobe Illustrator CC 2014. :)
The following images are a demonstration of how to use the template once printed.