Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
cognitiveSEO
Broad first-party SEO research coverage across links, rankings, keywords, competitors and site issues.
The homepage lists Site Explorer, Keyword Tool, competitor strategy research, backlink analysis, rank tracking and a comprehensive Site Audit: https://cognitiveseo.com/
Seobility
Useful keyword, competitor, backlink, and ranking research, but not positioned as an exhaustive enterprise research database.
The Keyword Research page supports seed, URL/domain, competitor, intent, volume, and top-10 ranking-page analysis: https://www.seobility.net/en/seo-content-tools/