MP3+G file support AKA Karaoke file support is now available in Serato DJ 1.7.4. Everyone secretly loves Karaoke.
These files come as two files, a .CDG file which contains the visual elements and an .mp3 file containing the audio. To add these to Serato DJ, you will need to unzip any zipped files and add both files to the Serato DJ library, which will show as one Karaoke file.
NOTE: The Serato Video expansion pack is required to display the visual component of Karaoke files. Learn more here: https://serato.com/dj/pro/expansions/video