Alexa Rank
One of the oldest systems is Alexa, allowing you to compare different domains. In addition to understanding the historical growth of visitors, you can also perform a competitive analysis.
Google Analytics
Google Analytics is a web analytics tool that provides aggregated information about the traffic that reaches your website based on audience, acquisition, behavior, and conversions that occur on the website.
These tools are not alternatives, but rather complementary, as they serve different purposes to perform an analysis that allows you to progress in the development of your systems.