What is some open source tool where reporting can be done?

As SSRS is product from Microsoft, it comes up with some cost. However, there are certain reporting tools which are available in the market. Please find below list:

NextReports

Jasper Reports

Pentaho

QueryTree

SharpDevelopReports

Seal Report

ELK Stack

Spago BI

ReportServer

Helical Height

There are many more tools which you can use. However free tools come up with some limited functionality and support. So before moving them to production, always check the criticality of your business functions.