I've seen this billboard mockup used by hundreds of designers to showcase their branding work. But I cannot locate where to source or purchase a .PSD mockup template for this. Can anyone help?
This is extremely simple, three layers only. On top the billboard as flat, no effects nor perspective
In the middle a wooden support structure for the billboard. It's so dark that any planks or drawn rectangles could be used. Even a shadow (=dark partially transparent rectangle) can do the job.
The lamps can be arbitary, even omitted. You can use a stock image of a billboard stand which has all parts, if needed or add fourth layer with some lamps.
In the bottom there's the building.
If you wanted just that building, the question of course is totally different and for it I haven't an exact solution. I can only suggest you to search for "red brick industrial building". Image stockers seem to have plenty of at least resembling photos.
BTW. You can make it better than your example. The photo of the building is curved, straightening it would make the perfectly rectangular billboard fit better.