mstsc on server core
There is no “install feature” method of doing this and I can imagine it's not supported by Microsoft. But you can add the RDP Client (mstsc) to server core by copying the following files from a server (preferably the same OS) with full GUI installation to the Hyper-V server:
From System32 folder:
- mstsc.exe
- d2d1.dll
- d3d11.dll
- dxgi.dll
- mstscax.dll
- msacm32.dll
From System32\en-US folder:
- mstsc.exe.mui
- mstscax.dll.mui