Model Context Protocol servers that extend AI capabilities
httpbin echo: GET/POST inspection, status codes, delay, UUID, base64. Debug aid.
Hugging Face Hub MCP — models, datasets, spaces
IETF Datatracker RFCs / drafts / working groups / people
INSPIRE-HEP high-energy physics literature database
ipify: caller IPv4/IPv6 echo. Useful for verifying gateway egress.
ISO country/language/currency/script code lookups (Debian iso-codes JSON)
Kitsu anime + manga catalogue (JSON:API)
Kraken keyless public market: time, status, assets, pairs, ticker, OHLC, depth, trades.
L2BEAT MCP — Layer 2 ecosystem analytics
Last.fm artist/album/track metadata (free API key required)
Launch Library 2 MCP — global rocket launch data
LeetCode public profiles, solved counts, daily question, problem detail.
Lemmy federated link-aggregator public reads (any instance)
Lens.org patent + scholarly search (free academic key required)
LibreTranslate MCP — open-source machine translation (BYO endpoint)
LibriVox public-domain audiobooks (~17000 titles in dozens of languages)
Lichess public API: players, ratings, eval, tablebase, opening explorer
Podcast directory search + best podcasts + recommendations via Listen Notes. Free key required.
Song lyrics lookup via lyrics.ovh
MalwareBazaar MCP — abuse.ch malware sample database (free, key required)
Mapbox geocode, directions, matrix, isochrones, map-matching, tilequery, static URL.
MAST (Mikulski Archive for Space Telescopes) — Hubble/JWST/Kepler/TESS
Maven Central MCP — Java/JVM artifact registry
MedlinePlus MCP — NIH consumer health info