AI Tools Directory
Honest pros and cons, who each tool is not for, and pricing dated to when we last checked it.
Search academic papers and see where the evidence actually lands.
ResearchFree · paid from $8.99/mo
Ask questions of a PDF and get answers with page references.
ResearchFree · paid from $19.99/mo
NotebookLM
8.5Turn your own documents into a grounded research assistant.
Verdict: The most trustworthy research assistant for working with your own material — source-grounding with passage-level citations is exactly how AI research should work. It only knows what you give it, which is both its limit and its point.
ResearchFree
Perplexity
8.3AI answer engine that cites its sources.
Verdict: The best tool for sourced, verifiable answers. For research and fact-finding it beats general assistants; for long-form writing or coding it isn't trying to compete.
ResearchFree · paid from $20/mo