Some additional noteworthy tools that you would be wise not to ignore are listed here, and you can find an even larger list on the TechNet wiki (http://social.technet.microsoft.com/wiki/contents/articles/5208.biztalk-server-2010-tools.aspx):
The ContextAccessor functoid (http://contextaccessor.codeplex.com/): This project contains a custom pipeline component and mapping functoid that allows you to access a message's context properties within maps executed within a receive pipeline or an orchestration.
Loopback Adapter (http://www.twoconnect.com/loopback-biztalk-adapter-free-download/): This is an adapter that allows you to loop back a message via a BizTalk send port, enabling some interesting patterns based on loose coupling.
BizTalk Deployment Framework (https://biztalkdeployment.codeplex.com/): This framework enables the automated build of near one-click installers for BizTalk solutions. It is especially powerful when combined with a build server.
BizTalk Server Functoids...