If you are stuck on upgrading to TFS 2018 due to the old deprecated XAML based builds, it can be a challenge to see how far you are from the goal of zero XAML builds.
When doing release management one of the first step is to get the artifacts from your buildjob copied to a remote machine. TFS already have some buildin tasks like Windows machine File Copy or the Azure File Copy task
The Azure file copy task uses the Azure scripts to copy files to the Blob or to the VM itself( it actually copies the files through the Azure LOB storage)
The Windows Machine File copy is using robocopy so it is meant for copying locally through the SMB protocol. However you might be blocked by a firewall that wont allow SMB.
Then PowerShell comes to the rescue. (As always)
Sometimes you need to get the latest successful build and get the download path for the artifact, for e.g. some 3 part tools or as an input for other build jobs.
Sometimes you need to get the workitems from TFS directly into your favorite tool, Powershell.
When the workitems are available in PS, you have a lot of possibilities, like making custom reports, release notes papers, or just plain lists.
But instead of creating your own query in PS, why not use the queries already in TFS.
Execution of test runs, either manuel or automatic, will create a bunch of diagnostic test data that can cause the the databse to crow quite rapid.
For vNext build /test jobs you define a retention policy, that will tell TFS how many days you want to keep the data (default 90 days). This job will run automatically every night.
But when using xaml based builds the retention policy is triggered on each build, so if you stop using a build definition, e.g. when you have relased and clone the definition, old builds and test data will be kept forever, until you trigger a build.