There is or can be a lot of crossover between promotional materials and collateral, which can sometimes be confusing. For my purposes, I'm viewing promotional materials as a sub-category of collateral, with a specific and narrower focus. Trade show materials are a good example, like booth graphics, banners, signs or giveaways including branded pens, cups, and note pads. Advertisements, maps, signage (also known as wayfinding or how to get from here to there), and billboards are some other examples.