JDiskReport enables you to understand how much space the files and directories consume on your disk drives, and it helps you find obsolete files and folders.

GrandPerspective is open source software for Mac OS X used for disk space analysis.

Stellar Drive Defrag is a drive defragmentaion utility.

DaisyDisk is a disk space analyzer for OS X.

DiskWave is a free disk usage utility for Mac OS X.

Monolingual is a program for removing unnecessary language resources from macOS, in order to reclaim several hundred megabytes of disk space.