Maybe you are looking for a free square poster or square flyer mockup on the web. This freebie may meet your needs.
Freebie created and released by David Scanu(Caen, France)
Feature of this Square Poster Flyer Mockup:
with or without clips,
fully editable as needed
papers folds,
light shine
blurred background (easy to change or edit)
License info: According to David Scanu, the author of this poster mockup,it’s published under Attribution-NonCommercial 3.0 Unported

Mockup-Square_Poster Flyer-With_Clips

Mockup-Square_Poster-Flyer-Without_Clips

Mockup-Square_Poster-Flyer-With_Folds-Without_Clips

Mockup-Square_Poster-Flyer-With_Folds-With_Clips

Mockup-Square_Poster-Flyer-With_Clips-With_Shine

Mockup-Square_Poster-Flyer-Without_Clips-With_Shine

Mockup-Square_Poster-Flyer-With_Clips-Blurred_BG

Mockup-Square_Poster-Flyer-Without_Clips-Blurred_BG

It’s very suitable for designers to showcase their square flyers or square posters using this mockup freebie.

You can download this Square Poster Flyer Mockup PSD file from here:  Download it here for free

Download it from this link if the author’s blog is down.