Check out the well-looking and photo-realistic wrinkled plastic A4 paper mockup design. You can change the background color and turn on the shadows to get a different scene. The template is straightforward to adjust by simply putting your images via Smart Objects. PSD file, dimension of 3238×2160 px at 300 dpi.
This mockup is a free piece taken from premium A4 Paper Stationery Mockup Bundle, and you can check it out at Creative Market.