Perplexity
Perplexity
ToolSearch & exploreBeginnerFree core · paid extras
For: Operators building an initial source landscape before committing to an explanation.
Why explore: Fast, source-linked web research.
Collection
The AI Research Stack
30 free tools for finding better answers
30 of 30 resources
ChatGPT Search
OpenAI
ToolSearch & exploreBeginnerFree core · paid extras
For: Investigators refining broad questions and comparing angles.
Why explore: Exploratory web research with sources and follow-up questions.
Gemini Deep Research
ToolSearch & exploreBeginnerFree core · paid extras
For: Questions that need several lines of inquiry, not one search pass.
Why explore: Multi-step research reports across sources.
You.com
You.com
ToolSearch & exploreBeginnerFree core · paid extras
For: Teams comparing what different retrieval systems surface.
Why explore: AI search and research with alternative retrieval options.
Brave Search
Brave
ToolSearch & exploreBeginnerFree
For: Researchers validating AI results against a non-Google index.
Why explore: Independent web index for coverage checks.
Semantic Scholar
Semantic Scholar
ToolScientific evidenceBeginnerFree
For: Evidence-led questions across scientific literature.
Why explore: AI-powered academic paper discovery and citations.
Consensus
Consensus
ToolScientific evidenceBeginnerFree core · paid extras
For: Moving from intuitive claims to study-backed inquiry.
Why explore: Answers grounded in published studies.
Elicit
Elicit
ToolScientific evidenceBeginnerFree core · paid extras
For: Systematic comparisons of methods, findings, and limits.
Why explore: Literature review and structured study comparisons.
Ai2 Asta
Allen Institute for AI
ToolScientific evidenceBeginnerFree
For: Niche scientific questions outside usual search vocabulary.
Why explore: Natural-language discovery of hard-to-find papers.
Paperguide
Paperguide
ToolScientific evidenceBeginnerFree core · paid extras
For: Building an initial evidence base before deeper analysis.
Why explore: AI-assisted academic search with synthesized answers.
ResearchRabbit
ResearchRabbit
ToolMap knowledgeBeginnerFree core · paid extras
For: Expanding from seed papers into overlooked literature.
Why explore: Related papers, authors, and citation exploration.
Connected Papers
Connected Papers
ToolMap knowledgeBeginnerFree core · paid extras
For: Understanding how ideas connect in a field.
Why explore: Visual clusters of related scientific work.
Litmaps
Litmaps
ToolMap knowledgeBeginnerFree core · paid extras
For: Tracking how a research area develops.
Why explore: Citation networks and topic evolution over time.
OpenAlex
OpenAlex
ToolMap knowledgeBeginnerFree
For: Analyzing institutions, topics, and citation structure.
Why explore: Open scholarly metadata at scale.
Google Scholar
ToolMap knowledgeBeginnerFree
For: Following how later work confirms or challenges a study.
Why explore: Broad academic search and cited-by tracing.
Gemini Notebook
ToolRead & synthesizeBeginnerFree core · paid extras
For: Comparing forecasts or claims across a controlled source set.
Why explore: Source-grounded Q&A across documents you select.
SciSpace
SciSpace
ToolRead & synthesizeBeginnerFree core · paid extras
For: Understanding methods and findings outside your discipline.
Why explore: AI-assisted reading of technical papers.
Explainpaper
Explainpaper
ToolRead & synthesizeBeginnerFree core · paid extras
For: Unpacking technical language without losing nuance.
Why explore: Contextual explanations of dense paper passages.
Anara
Anara
ToolRead & synthesizeBeginnerFree core · paid extras
For: Organizing multi-document research with traceable claims.
Why explore: Document workspace with source-linked answers.
ChatPDF
ChatPDF
ToolRead & synthesizeBeginnerFree core · paid extras
For: Locating support for claims inside long reports.
Why explore: Conversational Q&A on a single PDF.
Google Trends
ToolData & trendsBeginnerFree
For: Hypotheses about attention, terminology, and momentum.
Why explore: Relative search interest over time and region.
Our World in Data
Our World in Data
ToolData & trendsBeginnerFree
For: Historical baselines for economic and social claims.
Why explore: Open global datasets and evidence-based charts.
Data Commons
ToolData & trendsBeginnerFree
For: Cross-region comparisons before causal investigation.
Why explore: Connected public statistics and indicators.
GDELT Project
GDELT
ToolData & trendsBeginnerFree
For: Geographic and temporal shifts in coverage.
Why explore: Global news events and media attention patterns.
Hugging Face Papers
Hugging Face
ToolData & trendsBeginnerFree
For: Following new AI techniques and follow-on code.
Why explore: Emerging machine-learning research discovery.
Google Fact Check Explorer
ToolVerify & preserveBeginnerFree
For: Validating striking statistics before reuse.
Why explore: Search published fact-checks on public claims.
Wayback Machine
Internet Archive
ToolVerify & preserveBeginnerFree
For: Checking how public claims or product pages changed.
Why explore: Historical snapshots of public webpages.
Zotero
Zotero
ToolVerify & preserveBeginnerFree
For: Preserving sources and why each one mattered.
Why explore: Reference management and citation libraries.
Crossref
Crossref
ToolVerify & preserveBeginnerFree
For: Confirming publication details before citing.
Why explore: Scholarly metadata and DOI verification.
PubMed
NLM / NIH
ToolVerify & preserveBeginnerFree
For: Health and life-science claims independent of AI summaries.
Why explore: Biomedical literature search and verification.
About this collection
This is the searchable companion to The Strategy Stack's AI Research Stack on Substack.
Use it when you need a credible tool for a specific research stage—not another undifferentiated list.
Filter by research stage, cost, and format. Each entry includes an original summary and a direct link to the provider.
Start with search and explore when framing the question. Move toward evidence, mapping, synthesis, trends, and verification as your investigation matures.
For narrative context, workflows, and the six-stage research map, read the full editorial guide on Substack (linked on this page).
Read the full editorial guide on Substack ↗