ncdu, TreeSize, WinDirStat, DaisyDisk, WizTree, SpaceSniffer, Baobab Disk Usage Analyzer, FreeCommander, GrandPerspective, KDirStat, SpaceMonger, WhatSize, Disk Inventory X, SequoiaView, DiskUsage, crossdirstat, Diskitude, Grid Size File Manager, DiskSavvy, JDiskReport, Xinorbis, HDGraph, FolderSizes, Overdisk, xdiskusage, DiskWave, Space Radar, Directory Size Calculator, FilePro, TreePie, SquirrelDisk, K4DirStat, RidNacs, i.Disk, TDP x-Ray, 1Tree Pro, DirGraph, SpaceObServer, GetFolderSize, DiskMapper, Disk Space Fan Pro, Precious Disk, ClearDisk, DiskTriage, StepTree, Disk Space Finder, UtilStudio Disk Space Finder, Diskvision are some alternatives to Filelight.