There are numerous very large mounds of molehill soil visible in my local park, just begging to be collected. All finely sieved, as they do. But I've always wondered on the merits of such soil, and the pros and cons of going through the effort of collecting it. Would this be classed as topsoil, as I imagine it's been tunnelled up not that far from the surface. Cheers.
I used it on a regular basis in a previous garden.
As @wild edges says tho, if you are thinking of collecting from a public area, I'd advise against just in case it is contaminated.