"For Liberty!" is a short film on YouTube made by Plot Coalition, entirely in Unreal Engine. It follows Sergeant Isa Cruz as she is assigned to Judgement squad and is sent to investigate secret Automaton experiments on Terminids. They fight through the resistance of bugs and bots as she uncovers a hidden truth.
You can watch the film here:
Welcome to the Helldivers is a parody of a famous song by Bo Burnham called Welcome to the Internet. It talks about the game and what happens in it in a comedic tone.
You can listen to the song here:
Fans have created apps to track the progress of the Galactic War from across the world on any device. It can be an app on your phone or a tab in your browser. It's possible through unofficial, also fanmade APIs which can get you info about the liberation process of a planet, the current major order and other statistics.
An example, the Helldivers Companion App, probably the most famous:
https://helldiverscompanion.com