Keyword research tools, competitor analysis tools, backlink analysis tools
There are so many tools with plenty of plusses and minuses. For backlink data there is so much disparity & fluctuation, I prefer to use at least 3 different tools from different data sources. Same with keyword data.
The tools I have found most useful are crawlers. They can crawl thousands or hundreds of thousands of pages, mimicking search engine crawlers and giving me tons of different SEO data points to sift through. Examples include:
I'll have to second that. I also like Ahrefs. The clean and well thought out dashboards, the automated reports and the rich data set.
No wonder they are so successful. It just shows one can enter a crowded field and dominate it by providing a superior experience. There were plenty of SEO tools before Ahrefs but we didn't know what we were missing until they showed it to us!
Ahrefs is one great tool in Seo. In fact, Ahrefs is a Big Data like Google.
Usually in SEO, Ahrefs is a tool used to analyze rival websites, keyword research, marketing, opportunities to increase website traffic, build links (Backlinks), ...