I was more than pleasantly surprised when I found this poster mockup – all you need for presenting your work is in this one PSD file. It’s 2000 x 2000 pixels in height and width, extremely well organized in color coordinated layers which contain all wonders of this world: frames of different sizes, different kinds of backgrounds and shadows, some desk items like a cup of coffee, magnets, push pins, strings, clips and some other things, making your mockup a playground of options.
And it is entirely free for personal and commercial use! I highly recommend!
Check it out!