Any marketing tool which is used to market your brand online will be a digital asset for you. Many people do not even know which all assets they have to be used as a tool, Here are few of them just for an idea
Your website, Branded assets (logos, icons etc), Video content (video ads, product demos, etc), Images (infographics, product shots, company photos, etc), Written content (blog posts, eBooks, product descriptions, testimonials, etc), Online products or tools (SaaS, calculators, interactive content, etc), Reviews, Social media pages
Business first needs to categorise their asset then move on to develop a strategy about using then as a tool. The list of assets keeps on growing as they proceed with the campaigns. A library of such assets helps a lot while there is an immediate need for brand promotion. It minimises the time of creating fresh assets from scratch.