following are the tools which are very helpful while working with SharePoint Technologies. It save lot of time in development, deployment  and administration of SharePoint products.

SPDisposeCheck is a tool that helps developers and administrators check custom SharePoint solutions that use the SharePoint Object Model helping measure against known Microsoft dispose best practices. This tool may not show all memory leaks in your code and may produce false positives which need further review by subject matter experts.

http://archive.msdn.microsoft.com/SPDisposeCheck

Fiddler 2 supports debugging HTTPS traffic. If you want to bend the SharePoint without bending the rules. This  tool provide a great information on SharePoint.

http://www.fiddlertool.com/fiddler/version.asp

A graphical display of relogged perfmon files.

http://sqlperfmonanalyzer.codeplex.com/

Performance Analysis of Logs (PAL) Tool

http://pal.codeplex.com/

FileMon for Windows

http://technet.microsoft.com/en-us/sysinternals/bb896642

Introducing SQL Server Profiler

http://msdn.microsoft.com/en-us/library/ms181091.aspx

.NET Reflector

http://www.red-gate.com/products/dotnet-development/reflector/

Configure WCF Trace

http://msdn.microsoft.com/en-us/library/ms733025.aspx

Configure Workflow tracing

http://wiki.windowsworkflowfoundation.eu/default.aspx/WF/TracingWorkflowFoundation.html

http://msdn.microsoft.com/en-us/library/ee518966.aspx

ULSViewer allows users to open a ULS log file and display its contents in a user friendly format. Users can then perform advanced functions such as filtering, sorting, highlighting, loading logs, appending logs, etc in order to single out the data that is important to the user. This information can be used to diagnose problems with machines running ULS services, or to monitor machines and the events they create in realtime.

http://archive.msdn.microsoft.com/ULSViewer

Windows Identity Foundation (For Claims based Authentication)

http://msdn.microsoft.com/en-us/library/ee517292.aspx

How to write in event logs?