Currently, there is a limitation on which out of the box web parts can be displayed within full width sections, however, SharePoint Framework (SPFx) solutions can be configured to support full width display by setting the supportsFullBleed property to true.
@mytech1982 - This is an issue I am dealing with as well. Apparently, only Modern Experience "Communication" sites can utilize the full width page. Since our site was created as a "Collaboration" site, it appears we do not have access to the full-width-template. Why Microsoft has decided that we do not need a full-width page for Collaboration sites is lost on me. It is extremely frustrating embedding a list into a page, only to have it truncated by the column width while having about 40% of the screen real estate empty and un-utilized. We are in the process of updating our SharePoint Online site from an older classic experience to modern experience. So far, I like the modern experience list and library features. However, the UX design experience is a nightmare. Microsoft has chosen to adopt designs that maximize wasted space and providing no easy means to customize. Furthermore, Microsoft seems wholly opposed to borders or shading to distinguish sections. It is extremely frustrating. I believe in another decade this boondoggle of maximized negative space with no distinguishable elements will be considered the "web mullet" of the twenty-twenties, and will be looked back upon in like manner to the 3D/blinking/scrolling text of the nineties.