WinDirStat - WinDirStat is a disk usage statistics viewer and cleanup tool, inspired by KDirStat.
MiniTool Partition Wizard - As a partition magic alternative, Minitool Partition Wizard is the latest partition manager software which be used to manage partition on Windows 10/8/7/XP and Server 2003/2008/2012.
TreeSize - TreeSize tells you where precious disk space has gone to.
GParted - Extremely powerful partition manager. Copy, clone partitions.
SpaceSniffer - SpaceSniffer is a freeWare (donations are welcome) and portable tool application that lets you understand how folders and files are structured on your disks.
DiskGenius - DiskGenius provides an all-in-one solution for data recovery, disk partition management and backup & restore for Windows PCs, Servers and workstations.