I saw that many people have already written about this option but I will explain it as I thought of it. I came up with this idea after having to edit the products one by one to add a row I needed before the footer using Extra Content block. I could have solved it by creating a custom product layout but I didn't want to remount everything, unfortunately not the prefooter because I wanted the block to be only in the products.

I could have accomplished it with a couple of clicks if in the html block I could set where the block should be displayed like the layouts conditions which are very convenient. In the conditions it would also be useful to have the position as in “Extra Content Position”.

Another idea: in the theme options it is possible to add an html block before and after the add to cart button or using tabs (however so the content is hidden), but it could also be useful to have a hook after the header (e.g. to add a banner) and before the footer (e.g. to add an external review band). The idea of display conditions in html block remains better because allows to set custom content according to brand, categories, specific products and so on instead of being universal but maybe it's more difficult to achieve compared to those hooks in theme options.