"Resources and tools for difficult CTF (Capture The Flag) cybersecurity challenges" matching MCP servers:

Medicare claim documentation lookup for CPT codes against live CMS sources, returning structured requirements and document URIs with optional enrichment via RCI APIs.

MCP server that resolves postal/ZIP codes to place names, states, and coordinates using Zippopotam.us. Free, no API key required.

Enables real-time domain registration lookups via RDAP, including availability, expiration, and registrar details, with no API key required. Supports natural language queries like 'is example.com available?' or 'when does example.com expire?'.

Enables currency conversion and exchange rate lookups using real ECB reference rates, free and without an API key. Supports natural language queries like 'convert 100 USD to EUR' or 'what's the exchange rate between GBP and JPY?'.

Provides real, official public holiday data for ~100 countries with tools to list holidays for a year and check if a specific date is a holiday. Free, no API key required, powered by Nager.Date.

Provides real-time air quality data (US AQI, PM2.5, PM10, ozone, NO2, SO2, CO) for any city via natural language, using free Open-Meteo data and a single tool.

Provides real-time cryptocurrency prices, market cap, and 24h change using CoinGecko, with free access and no API key required.

An MCP server that lets AI models run code in 31 languages, evaluate symbolic math and logic problems, and measure complexity—exposed as 48 tools for execution, session management, translation, optimization, and more.

A MCP Server that lets user ask AI models to discover the collection of the Metropolitan Museum of Art. Adds the discovered art works as Resources on the server.

Creates Drake-style rap bars from any situation you type, and provides a complete MCP example with tools, resources, prompts, and an interactive UI widget.

Lets Claude fetch futures OHLCV bars with relative volume, capture TradingView charts for exact trading-day windows, and detect range setups with drawn support and resistance levels.

An MCP server for rendering common ECharts visualizations from structured tool arguments, exposing per-chart opener tools that map to independent HTML app resources.

An Excalidraw editor for DeepSeek Harness that lets AI models create, edit, and inspect diagrams, including image capture and revision management.

Provides live product search, offer comparison, and price history retrieval from BestPrice.gr through three read-only tools, enabling AI applications to query shopping data without an API key.

MCP server for creating and editing diagrams using draw.io. Allows generating diagrams from Mermaid or XML, searching shapes, and opening them in draw.io for export.

Enables users to draw GIS geometry on an interactive map and get clean, validated GeoJSON to hand off to other GIS MCP servers such as FEMA flood screening and USGS hydrography.

Embeds live, interactive Tableau dashboards in ChatGPT, pushing mark selections to the model so questions about specific data points are answered with live queried numbers.

Gives Claude read-only access to your ESPN fantasy football team, including roster, weekly matchup, free agents, and player profiles.

Search vacation rental properties, check real-time availability, get canonical pricing quotes, and create direct bookings. Each property is its own node with live data. Supports staircase pricing, seasonal rates, and 11 languages.

Provides AI assistants with direct access to Jamf official documentation, enabling them to answer Jamf-related questions by searching, retrieving articles, and browsing product documentation.