Elite Dangerous

Frontier twitch: FDev's official Twitch page for drops and information.

Inara: linking player account allows tracking of ships, engineering unlock progress, community goal progress, and looking up commodities and other information in the galaxy.

Galnet: a comprehensive archive of all galnet news articles dating back to June 3301/2015.

Elite Dangerous Shipyard: or "EDSY", the most current, up-to-date ship engineering tool and layout calculator.

Deep Space Support Array: a community of fleet carrier owners who have various services for deep space explorers away from the bubble.

Odyssey Map Guide: maps to all settlement types and key locations

Fleet Carrier Calculator: Helps calculate yearly upkeep cost, and initial lease of a fleet carrier from the Brewer Corporation.

Elite Dangerous Star Map: a parallel to Cannon's star map and database.

Elite Dangerous Market Connector: or "EDMC", the tool connecting Inara, and any other player resource to reading your in-game journal files. 

Some notable plug-ins:

Cannon plug-in: links to Cannon's website and helps complete database entries and expands knowledge of what is out there.

BGS-Tally: helps your local BGS coordinator with activities and participation.

Anti-Xeno combat playlist: this YouTube playlist has everything from staring to know key terms, to soloing high level interceptors.

Anti-Xeno ship builds: recommended starting builds, and the theory behind the builds, to modify all ships in game and how to get the most out of them for thargoid combat.

Thargoid specifications: Thargoid specs of all types to help understand them.

Thargoid War FAQ: Google Doc with information on the Thargoid war, and later how to build an AX ship that is survivable.

Starter Videos: a YouTube playlist compilation of helpful starter information on how to fly, fight tactics, and what to look out for.

Flight Assist Off starting: a youtube playlist of videos with techniques, drills, and helpful tips to get the most of flight assist off flight mechanics.

Anti-Xeno Initiative: A wealth's of information from multiple player groups/squadrons/independent pilots in efforts to reveal the history, fight mechanics, and lore of anything thargoids.

Burr Pit: good theories and explanations on the history of the game

Canonn Research Group:  an independent cooperative committed to science and discovering the mysteries of the universe; non-exclusive, open group that does not take part in politics and is adamantly neutral.

CQC Discord: matches, fight help, and anything regarding the CQC portion of the game. Ask what game mode is being used.

Fuel Rats: Refueling CMDRs anywhere in (or out of) the galaxy. No rescue is too difficult.

Hutton Orbital Truckers: another long standing hauling player group of multiple squadrons, known for the Hutton Mug.

Hull Seals: repairing CMDRs when their hulls are about to go and they need help.

New Pilots Initiative: a community built on getting new players on their feet.

Operation IDA: Repairing the galaxy after every invasion or incursion, consisting of multiple player groups/squadrons/independent pilots.