Which astronomical unit is commonly used alongside the light-year when measuring the vast distances of cosmic structures like galaxy filaments and sheets?

Megaparsecs

When astronomers attempt to quantify the immense sizes of structures like superclusters, filaments, and walls of galaxies, the fundamental unit often employed is the light-year, but more frequently, the megaparsec is used for conciseness. A megaparsec is explicitly defined as being equivalent to approximately 3.26 million light-years. This scale is necessary because the structures being measured, such as the Sloan Great Wall or the Quipu, extend across hundreds of millions or even billions of light-years, making smaller or intermediate units impractical for conveying their enormous spatial extent. These measurements describe the size of non-random aggregations of matter clumped together primarily by gravitational forces.