NirSoft.Net
TCPConnectProblemView
FreeA decent, free tool for diagnosing TCP connection issues
Windows
FileTypesMan
FreeManage and Modify Windows File Types Easily
Windows
BrowserDownloadsView
FreeFree Multilingual Utility Tool for Windows
Windows
PropertySystemView
FreePropertySystemView: Untested and Probably Unnecessary
Windows
IconsExtract
FreeEfficient Icon Extraction Tool for Windows
Windows
CurrPorts
FreeComprehensive Network Monitoring with CurrPorts
Windows
SmartSniff
FreeComprehensive TCP/IP Packet Capture Tool
Windows
RegScanner
FreeEfficient Registry Search Tool for Windows
Windows
BluetoothView
FreeSimplifying Bluetooth Device Connectivity
Windows