here is a quick list that i always use... may be it's helpful for all. 

Health and Administration

• BizTalk Management Tool Pack (http://btstoolpack.codeplex.com/)
• BizTalk Best Practice Analyzer (http://www.microsoft.com/downloads/details.aspx?FamilyID=93d432fe-1370-4b6d-aaa8-a0c43c30f5ab&displaylang=en)
• Server Performnace Advisor: (http://www.microsoft.com/downloads/details.aspx?familyid=09115420-8C9D-46B9-A9A5-9BFFCD237DA2&displaylang=en)
• Message Box Viewer(http://blogs.technet.com/jpierauc/archive/2009/04/27/mbvquerybuilder-latest-version.aspx )
• PAL(http://pal.codeplex.com)
• Orchestration Profiler(http://biztalkorcprofiler.codeplex.com/)
• SQL Server 2005 Performance Dashboard Reports: (http://www.microsoft.com/downloads/details.aspx?familyid=1d3a4a0d-7e0c-4730-8204-e419218c1efc&displaylang=en)
• Powershell and BizTalk: http://biztalkmessages.vansplunteren.net/tag/biztalk-tools/

Deployment

• BTS Control(http://btscontrol.codeplex.com/)
• View BizTalk Assemblies Option in My Computer: BTSASMEXT.DLL(http://msdn.microsoft.com/en-us/library/ee251587(BTS.10).aspx): Do not panic if you do not find the dll in your production/UAT box. The DLL is installed as a part of Visual studio integration. I have tested it by copying the dll to a different server where BizTalk is installed and registered it(You have to logoff and logon to take affect). The next time I logon the BizTalk Assemblies option is available in My Computer.
• BizTalk Documenter(http://biztalkdocumenter.codeplex.com/)
• BizTalk SSO Configuration Data Storage Tool (http://blogdoc.biztalk247.com/article.aspx?page=629fb9d6-7af1-4e02-b6d1-5cd5c554f057)
• Deployment Framework for BizTalk (http://biztalkdeployment.codeplex.com/)
• BizTalk Undeploy Helper (http://biztalkundeploy.codeplex.com/)
• BizTalk Host Configurator per Application (http://biztalkapphostconfig.codeplex.com/)

Testing & Development

• Microsoft BizTalk LoadGen 2007 tool(http://www.microsoft.com/downloads/details.aspx?FamilyID=c8af583f-7044-48db-b7b9-969072df1689&DisplayLang=en )
• BizUnit(http://www.codeplex.com/bizunit)
• BizTalkCop & FXCop(http://biztalkcop.codeplex.com/)
• Map Documenter http://biztalkmapdoc.codeplex.com/

Relate Tools

• DebugView for Windows (http://technet.microsoft.com/en-us/sysinternals/bb896647.aspx)
• Process Explorer(http://technet.microsoft.com/en-us/sysinternals/bb896653.aspx)
• TCP Trace(http://www.pocketsoap.com/tcptrace/)
• TCP View(http://technet.microsoft.com/en-us/sysinternals/bb897437.aspx)
• Sys Internals(http://technet.microsoft.com/en-us/sysinternals/bb842062.aspx)
• DTC Ping(http://www.microsoft.com/downloads/details.aspx?FamilyID=5e325025-4dcd-4658-a549-1d549ac17644&DisplayLang=en)
• DTC Tester(http://www.microsoft.com/downloads/details.aspx?FamilyID=5e325025-4dcd-4658-a549-1d549ac17644&DisplayLang=en)

Enterprise Service Bus

• http://esb.codeplex.com/
• v2.0 : http://msdn.microsoft.com/en-us/biztalk/dd876606.aspx - BizTalk Server 2009
• v1.0 : http://msdn.microsoft.com/en-us/library/cc487894.aspx

Guides:

• Microsoft BizTalk Server Performance Optimization Guide http://www.microsoft.com/downloads/details.aspx?familyid=98ECF11A-9A8E-4939-8CEF-2BC5536DC792&displaylang=en
• BizTalk Server Database Optimization http://msdn.microsoft.com/en-us/library/bb743398(BTS.10).aspx
• Microsoft BizTalk Server Operations Guide http://www.microsoft.com/downloads/details.aspx?FamilyID=5251F103-329D-4F8D-95B5-64F99F2F6DFC&displaylang=en
• Business Activity Monitoring in Depth for Developers http://www.microsoft.com/downloads/details.aspx?familyid=FF6E4498-B1FF-4932-BA6B-1B53AC6FB3B2&displaylang=en

Blogs:

• Server Team: http://blogs.msdn.com/biztalk_server_team_blog/
• biztalk: http://blogs.msdn.com/biztalk/
• http://blogdoc.biztalk247.com/default.aspx