I usually refer to marketing as "air cover" and sales as the "infantry." Since they deal with leads directly, they have to make it look like they customize pieces specifically for the client. What we do is create generic pieces, infographics, case studies, etc that they insert inside a customized piece/email they create.Since most of their communication is done through email, it makes it really easy.
For presentations, we build templates in a way so that all they have to do is switch out logos and/or delete pages in powerpoint. No other customizations needed since they are not graphic designers.