Which SEO tools you like most and why?

I have found SEMrush to be the most beneficial SEO tool for my current work on my clients' website (https://trainspeedtest.in/). Its comprehensive features, such as keyword research, competitor analysis, and site auditing, have greatly aided in optimizing their online presence. SEMrush's user-friendly interface and reliable data have consistently delivered valuable insights, enabling me to make informed decisions and enhance their search engine rankings effectively.