Here's the templates I made and use for making my own zines.
I use a Canon IP8720 printer, Wescott guillotine, and stapler to make my zines. If you don't have those tools, you can hand-draw on your own sheet of paper, and cut with scissors.
For image editing, I use an old copy of Photoshop CS6. That was free when I got it 5000 years ago. I will recommend some other free options below.:
Produces one 16-page zine, with a single sheet of 8.5×11 paper, and double-sided printing. You can probably stretch this template for smaller or larger sizes of paper.
Produces two 8-page mini zines, on a single sheet of of 8.5×11 paper, with double-sided printing. This template makes one more zine compared to the most popular 8 page zine template.
Follow the same instructions as the 16 page zine.