In Google Display Ads, remarketing displays web ads to people who have already visited your website or application. Since they have left the web resource without conversion, the ads make the users return. This way, standard and dynamic remarketing ads share the same goal but offer different approaches to achieve it.
Standard remarketing is the use of remarketing lists to display generic ads. For example, you create a list of users who have been on your web resource but left and remind them about your brand with ads.
Dynamic remarketing is more sophisticated. It allows you to show the products or services users have viewed on your website during the previous visits. The message is tailored to a specific target audience and, therefore, more effective. Dynamic ads also support real-time bid optimization that calculates the best bid for each impression and saves you money.
What two types of remarketing can be used on Google Display Ads? https://support.google.com/google-ads/answer/3124536