1. NetWrix Account lockout Examiner (Freeware)
This is a nice free tool. It will show what are the servers / workstations that particular account is in disconnected state / locked.
2. Microsoft Baseline security Analyzer (Freeware)
Current version 2.2. http://www.microsoft.com/en-us/download/details.aspx?id=7558
3. Perfmon – Performance Monitor (builtin free tool)
Run -> Perfmon
4. RVTools (freeware)
To login Linux machines from Windows OS.
5. Tree Size free / Professional
To view the folder size. Professional version is needed to view folder size of remote machines.
RemoteRebootx is a cool tool used to mass ping or mass reboot remote servers and clients.
7. Free tools from Manage Engine
8. vSphere client download link: