The UUU mod lets you trigger a free cam mode in a lengthy list of Unreal Engine 4 games (more than 300, according to UUU's creator), disable HUDs, and recreate the in-game console. Plus it adds a frame skip function. The result is a lot of freedom to capture exactly the right moment—even during cutscenes, which are usually off-limits.
It's also a ticket to wander through game environments that either go underappreciated or missed entirely, like the cyberpunk cityscapes of The Ascent