Research depth
Discovery
How well the tool supports keyword, competitor, SERP, backlink, or market research before execution.
Dragon Metrics
Deep keyword, competitor, backlink, SERP, and global search-engine research capabilities.
Keyword Research provides search volume history, intent, difficulty, organic CTR, fresh SERPs, filters, keyword lists, competitor research, and Keyword Gap: https://www.dragonmetrics.com/product-tour/keyword-research/
WriterZen
Broad SEO research spanning topics, keywords, clustering, SERP/domain analysis, and keyword planning.
The product navigation lists Topic Discovery, Keyword Explorer, Keyword Planner, and Domain Analysis; Keyword Explorer also describes wildcard, Allintitle, and revenue forecast workflows. https://writerzen.net/ and https://writerzen.net/products/keyword-explorer