There is only one file type that uses the .NCGR extension:
Nintendo DS Title Graphics File
Title screen graphic used by some games for the Nintendo DS handheld console, such as Mario Kart; saves a collection of graphic tiles that make up a picture when arranged on the screen; stored with a color palette (.NCLR) file and an .NSCR file that contains the locations and rotation information for placing the image tiles.
NCGR files can be edited with MKDS Course Modifier and Crystal Tile 2.
Updated: April 11, 2012