"Free Graph and Network Visualization Tools (No API Key Required)" matching MCP servers:

Provides tools for AI-powered graph analysis, including relationship extraction, adjacency matrix creation, and network centrality calculations. It enables users to perform complex structural analysis and generate interactive D3.js visualizations from structured data.

Enables natural-language spatial analysis of transmission lines and wildlife/public access lands using Claude, MCP, and DuckDB. Users can ask questions about intersections, distances, buffers, and other GIS operations without writing SQL.

Enables LLMs to perform OSINT link-analysis by exposing transforms (DNS, WHOIS, Shodan, etc.) as MCP tools for autonomous investigation and graph enrichment.

Enables access to Japanese stock market data via the free J-Quants API, providing tools for company search, daily quotes, and financial statements.

Verified AI free-tier limits, quota comparisons, commercial-use verdicts and zero-cost workflows. Every entry carries a human-checked verification date and is re-checked by a daily link patrol.

An MCP server exposing the EU Birds Directive Art. 7(4) 'Key Concepts' data: the periods of reproduction and pre-nuptial migration for each huntable bird species in each Member State. It lets you check whether a given hunting-season date falls within a protected period.

MCP server for key driver and feature importance analysis based on rule mining

Provides actionable financial intelligence tools for AI agents including insider buying signals, earnings IV plays, market pulse, stock analysis, and options strategies via free public data sources.

An MCP server for HF radio propagation analytics using the IONIS dataset collection, enabling natural language queries about band conditions, propagation paths, and solar correlations.

Gives Claude direct access to the Africa API for comprehensive data on all 54 African nations, including economic indicators, markets, trade, government, elections, and policies.

Provides five rigorous reasoning protocols (debate, red team, audit_argument, threat_model, check_study) that run on the AI you're already using, requiring no extra API keys or costs.

Enables access to live precious metals prices, historical data, market intelligence, and portfolio management with AI/LLM integration.

An MCP-native pipeline for collecting structured intelligence on higher education institutions using the WHED schema, enabling scraping, extraction, validation, and saving of profiles.

Provides a read-only API over a book catalogue, offering tools to search books, retrieve book details and series, and inspect provenance and source agreement data.

Zero-auth hosted MCP for AI builders: optimize/convert images (WebP/AVIF/JPEG), paste-ready SVG QR codes, plus cited Cleanor Labs data on device storage capacity and next-gen image-format savings. No API key or signup.

Provides AI agents with Korean national fiscal data (budgets, settlements, and fiscal programs) from multiple government APIs through 7 tools, enabling natural language queries.

Gateway connector between LLM agents and world data, providing access to financial market prices, macroeconomic indicators, and news through a bundled endpoint catalog.

An MCP server for managing pandoc/CSL-YAML bibliographies and verifying citations in documents.

40-tool colour intelligence API for AI agents. Cultural risk, archive-verified colour naming, palette generation, WCAG accessibility, material physics, ecommerce copy, and image generation briefs. 16,682+ named colours across 43 cultural archives.

MCP server for the Infobel GetData API, enabling AI agents to search businesses, retrieve records, and browse categories and locations.