H2testw - Flash drive test utility written by Herald Bögeholz. Writes full flash drive space with test data then tries to reads it back and verity integrity. Good for detecting counterfeit flash drives that report their size larger than actual flash memory inside. An alternative tool, with more options (ChkFlsh) can be downloaded from here.
Intel Burn Test (v2.54) - CPU stress test utility. Can't link to developer's website (AgentGOD) as his domain seems to be suspended...
WakeOnLan - Simple WOL packed sender / receiver
WinSCP - Open source free SFTP client and FTP client for Windows. Can be used to access Linux server filesystem from Windows. More info
RealVNC - Free version of RealVNC 4.1.2. More Info
Windows Installer Cleanup utility - Microsoft .msi installations cleanup (hard removal).
inSSIDer - Wi-Fi network scanner. More info
Beyond Execute - Execute processes on remote computers. Command line tool. More info
My Uninstaller - Displays the list of all installed applications with product name, company, version, uninstall string, installation folder and more. More info
Autoruns - Shows what programs are configured to run during system bootup or login. More info
7-Zip Portable - File archiver utility.
Process Explorer - Find out what files, registry keys and other objects processes have open, which DLLs they have loaded, and more. More info
Process Monitor - Advanced monitoring tool for Windows that shows real-time file system, Registry and process/thread activity. More info
Orca - Database table editor for creating and editing Windows Installer packages (MSI) and merge modules. More info
Filemon - Monitors and displays all file system activity on a system. Replaced by Process Monitor
Robocopy - (Robust File Copy) Command-line directory replication tool. More Info