PowerShell modules can be found in the Dynamics SDK’s.

Microsoft Dynamics 365 (v8.x), Microsoft Dynamics CRM 2016 (on-premises), and the User Interface Integration (UII) SDK – https://www.microsoft.com/en-us/download/details.aspx?id=50032

Details can be found at: https://docs.microsoft.com/en-us/powershell/powerapps/get-started-connector?view=pa-ps-latest

Dynamics 365 (9.x) – The tooling for this version is available via NuGet packages. More information can be found at https://docs.microsoft.com/dynamics365/customer-engagement/developer/download-dynamics-365-sdk-v9