The Microsoft Fasttrack portal includes a branding toolkit full of Microsoft 365 and Office 365 app icons which are very useful for internal communications. That’s an important point. While you might like to use the icons in external communications, like blog posts or presentations given at conferences, Microsoft doesn’t license their use for those purposes. But will Microsoft come after you if you slip a SharePoint or Teams logo into your next presentation. Probably not, as long as you use the icons tastefully.