.pk4 files?In the context of Doom 3, .pk4 files are essentially compressed archive files (similar to .zip files) that contain the game's assets. They hold the textures, models, sounds, maps, and scripts that the game engine runs.
But if you are using classic dhewm3:
Doom 3: Resurrection of Evil is a first-person shooter video game developed by id Software and released in 2005. It's an expansion pack for Doom 3, offering new levels, gameplay mechanics, and a continuation of the original game's storyline. doom 3 resurrection of evil pk4 files download
Community Repositories: Sites like the Internet Archive host older versions of the expansion for archival purposes, though these may require an original CD key to function. Useful Enhancements and Fixes Steam: Sold as Doom 3 or part of the DOOM Bundle
No — legally and practically, PK4 files are copyrighted game data.
You cannot download them separately without owning the game. But if you are using classic dhewm3 :