Template for what domain/business/requirement?
During my career I saw and create so many reports, all very different in datasource, content and design.
I can't imagine one could create a meanfull template for a wide range of business.
But you can find some examples on Internet, like https://www.numerro.io/guides/top-10-power-bi-dashboard-examples-free-template
BTW, PowerBI is not supported here on Q&A, better post at https://community.powerbi.com/t5/Forums/ct-p/PBI_Comm_Forums