The MSDN docs state that I can find the WCF Test Client in:
C:\\Program Files\\Microsoft Visual Studio 9.0\\Common7\\IDE\\
VS 2019 Professional:
C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\Common7\IDE\WcfTestClient.exe
VS 2019 Community:
C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\Common7\IDE\WcfTestClient.exe
VS 2019 Enterprise:
C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\IDE\WcfTestClient.exe
VS 2017 Community:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Community\Common7\IDE\WcfTestClient.exe
VS 2017 Professional:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Professional\Common7\IDE\WcfTestClient.exe
VS 2017 Enterprise:
C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\WcfTestClient.exe
VS 2015:
C:\Program Files (x86)\Microsoft Visual Studio 14.0\Common7\IDE\WcfTestClient.exe
VS 2013:
C:\Program Files (x86)\Microsoft Visual Studio 12.0\Common7\IDE\WcfTestClient.exe
VS 2012:
C:\Program Files (x86)\Microsoft Visual Studio 11.0\Common7\IDE\WcfTestClient.exe