These can ofcourse be dynamic content!
This is the team that build this! This could perhaps be the lastest news blog article or something like that.
Add any RSS feed URL to this Custom Dynamic Source and use its content in your Dynamic Builder setup. In example you can add a external news websites feed in a builder Grid element or perhaps get a Podbean.com feed in a nice List element. Or you can perhaps integrate a medium.com publication (example rss feed: https://medium.com/feed/@Medium). Most services today do have a RSS feed option like SoundCloud.com, Medium.com, Prezly.com, Podbean.com etc. Your imagination is the limit!