What are the best sites to advertise job openings when trying to hire college and university students?

Until on-campus recruitment essentially shut down in the spring of 2020 due to Covid, the vast majority of students and recent graduates were hired through on-campus recruitment by large employers.

Today, it is still true that most are employed by large employers but what is no longer true is that the hiring is done almost exclusively through on-campus efforts. In 2020 and 2021, these large employers were forced to modernize and many discovered that they could exponentially accelerate their time-to-hire and reduce their cost-to-hire by using virtual sourcing tools like job boards. Some of those job boards were general like Indeed, LinkedIn, and Jooble. Others were niche like College Recruiter. 

The best advertising channel is not one advertising channel. Every good carpenter knows that their tool bucket needs to have a variety of tools to get the job done. Similarly, every good recruiter knows that their sourcing bucket needs to have a variety of tools to get the job done.