is there a (simple) way to move a single TeamProject from one collection to another (in one server) in TFS 2010? Including source code, work items, documents, project site...
No not really simple, you can split a collection and creata a new collection with the team projects you move in it, but you cannot out-of-the-box merge a team project into an existing collection.
What you can do is to use the TFS integration platform http://visualstudiogallery.msdn.microsoft.com/eb77e739-c98c-4e36-9ead-fa115b27fefe or http://tfsintegration.codeplex.com to migrate your team project over to the new collection. This is however a DataMigration that doesnt keep or even move all data, but it will move Source Code & Workitems. Moving a team project site (if needed) , including documents can be done by using the STSADM Export and Import commands, please refer to http://technet.microsoft.com/en-us/library/cc288191%28v=office.12%29.aspx for more info about moving SharePoint sites
No there isn't.
But it is a requested feature: http://visualstudio.uservoice.com/forums/121579-visual-studio/suggestions/2037613-make-it-possible-to-move-a-team-project-between-te
Yes there is a feature request, but I don't think it will be shipped in the box, so the other option to use TFS Integration Platform
It is not easy, but it is doable: Split a Team Project Collection
There is a way to move from one collection to another using git-tfs and git-tf tools, it is a kind of workaround, but works if this is really required to be done.
This is posted step-by-step here: https://fabiostawinski.wordpress.com/2017/03/22/tfvc-to-git-to-tfvc-is-it-possible/
In VS 2013 - map both collections to some folders, and then "Move" command will be available:
来源：https://stackoverflow.com/questions/10100406/moving-a-team-project-from-one-collection-to-another