Astronomy
- Amateur Astronomy Guide: Listing of local astronomy clubs
- APOD: Picture of the day from NASA
- ClearDarkSky: Forecasts of astronomical observing conditions
- DarkSiteFinder.com: Light pollution maps
- Heavens-Above: Information on satellites
- HubbleSite: Hubble space telescope news releases
- International Dark-Sky Association: Light pollution advocacy organization
- SpaceWeather.com: Sun-Earth environment information
- Stellarium Web: Online planetarium
- The Astronomy League: Amateur Astronomy interest organization
Astronomy News
- Astronomy Magazine: An astronomy magazine
- Sky & Telescope: An astronomy magazine
- Star Gazers: Weekly 5 minute PBS television series on naked eye astronomy
- Universe Today
Astronomy Products
- Celestron
- Miller Engineering: Discs for Homestar
- Orion Telescopes & Binoculars
- Sega Toys Homestar and Astrial: Home planetarium and Discs
Computer Products
- Digital Loggers: Sellers of the Atomic Pi x86_64 Atom SBC
- Nvidia Shield: Android TV set-top box for video and gaming
- Obihai: SIP and Google Voice gateways
- Raspberry Pi: ARM SBC
- Synology: NAS Devices
Computing
- Free Software Foundation: Advocating free software ideals
- Open Source Initiative: Promoting open source software
- OpenDocument Format: Free and open document format
- Wikimedia Foundation: Sharing human knowledge
- World Wide Web Consortium: Ensuring the long-term growth of the Web
Ham Radio
- Amateur Radio Service at FCC.gov: Amateur radio information and licensing
- American Radio Relay League: Amateur Radio interest organization
- aprs.fi: Google Maps APRS
- eHam.net: Amateur radio community site
- HamTestOnline: Ham radio exam courses
- learn morse code: Morse code charts
- Morse Resource: Tools to help learn or improve your Morse code skills
- QRZ.COM: Amateur radio database, news, forum, swap meet, and exam preparation
- RadioReference.com: Radio frequency database and resources
- Universal Licensing System at FCC.gov: Public access to FCC licensing information and electronic filing
- VOACAP: Point-to-Point HF Prediction
- W8IRC: Ham radio related IRC channels
- Worldwide Ham Radio QSL: Solar-terrestrial data
- WSPRnet: Weak signal propagation reporter network
Ham Radio Products
- Alpha Antenna: HF Verticals and J-Poles, and satellite antennas
- Argent Data Systems: Makers of the OpenTracker APRS
- Arrow Antennas: VHF and UHF portable, yagi, and J-Pole antennas
- KF7P Metalwerks: Tower, shack, and grounding gear
- MFJ Enterprises: Amateur radio accessories
Internet Services
- Dreamhost: Hosting company of this website
- Freenode: IRC network
- Gmail: Google email services
- Google Voice: Google telecom services
- No-IP: Free dynamic DNS and managed DNS provider
- SIPThor Net: Provides free SIP accounts
- Twitch: Live streaming platform
Music and Percussion
- 8notes.com: Free sheet music
- Association of Concert Bands
- Blank Sheet Music .net: Free printable staff paper
- makeamarimba.com and buildavibraphone.com: Purchase building plans for a mallet instruments
- Percussive Arts Society
- Petrucci Music Library: Library of public-domain music scores
Music: Local Groups
Music: Products
- Evans Drumheads and Promark Drumsticks
- Jarvis Industries: All-terrain band hardware
- Meinl Percussion and Meinl Cymbals
- Musser Mallets
- Trixon Drums USA
- Vic Firth and Balter Mallets
- Wernick: Xylosynth and Accessories
- Zynthian: Open platform for sound synthesis for Raspberry Pi and Linux
Music: Stores
Programming: Automation
Programming: Java Libraries
Programming: Languages
Programming: MathStat
Programming: Web
- Fast.com: Internet speed test
- Speedtest.net: Internet speed test
- The HTML5 Test
- W3C CSS Validation Service
- W3C Feed Validation Service
- W3C Link Checker
- W3C Markup Validation Service
- W3Schools: Web development tutorials and references
- When can I use...: Compatibility tables for web browsers
Retrogaming
- 8BitDo: Retro themed controllers and accessories
- Bingo Boards
- Newer Team: Mods of Mario
- Retro Game Restore: Maker of the GPiMate
- RetroFlag: Retrogaming cases and classic controllers
- speedrun.com: Speedrunning leaderboards
Retrogaming: Randomizers
- A Link to the Past Randomizer
- Archipelago: Multi-Game Multi-World Randomizer
- FF1 Randomizer and Beta
- FF4 Free Enterprise: Randomizer
- FF5 Career Day: Randomizer
- FF6 Worlds Collide: Randomizer
- HMS Jayne and dev: Final Fantasy I & II: Dawn of Souls (GBA) Randomizer
- LADXR: Links Awakening DX Randomizer
- Ocarina of Time Randomizer
- OoTMM: Ocarina of Time and Majoras Mask Crossover Randomizer
- Oracles Randomizer: Randomizer for Oracle of Ages and/or Seasons
- Super Mario RPG Open World Randomizer
- Super Mario World Randomizer
- Super Metroid and ALttP Crossover Item Randomizer and Beta
- Super Metroid VARIA Randomizer
Space Exploration
- ESA: The European Space Agency website
- NASA: The National Aeronautics and Space Administration website
- Space Frontier Foundation: American space advocacy group
- The Planetary Society: Space exploration interest organization