Leave a useful link in the comments and I will add it

Emergency

• Emergency: 911
• DragonCon Security – Marriott Rooms L405 and L406 – 404-586-6316
• Georgia Traffic Info: 511
  • Hit 1 in the menu to request a HERO unit for vehicle emergencies (flat tire, out of gas, breakdown, etc)
• Georgia Poison Control Hotline: 1-800-222-1222 or 404-616-9000
• Grady Memorial Hospital (nearest to the D*C host hotels, use 911 first for medical emergencies): 404-616-1000

Getting to DragonCon

• Ticket Purchase
• Packing List
• Hotels
• Transportation

Schedule

• DragonCon Official App Android iOS
• 2018 Dragon Con Schedule Grid On Google Sheets
• DragonCon Parade – CBS

Social Networking

• DragonCon on Facebook
• DragonCon on MySpace
• DragonCon on LiveJournal
• DragonCon on Discord
• DragonCon Official Twitter
• DragonConTV on Twitter
• Items with the #DragonCon tag on Twitter
• DragonCon on Reddit
• DragonCon on Instagram

Unofficial Guides

• Dementia’s “Everything you want to know about Dragon*Con” post (via LiveJournal)
• Cosplay.com’s How to Survive Dragon*Con thread (via Cosplay.com)
• Lycorne’s Rules & Tips for Con’ Roomates post (via LiveJournal)

Food

• The Hub at Peachtree Center – Directions
• Suntrust Food Court – Directions

Photo Galleries

Fan Photo Galleries

Maps

• Marta Rail Map
• Google Map with landmarks
• Downtown parking map
• Hyatt Convention Levels Map 

Forums

• DragonCon LiveJournal
• Cosplay.com
• DragonCon Forum
• DragonconForums.org

Costuming Groups

Not DragonCon specific, but maintain a strong presence.

• 300 (Spartans): https://www.300dc.com/
• Battlestar Galactica: The Colonial Fleet
• 501st Legion (Stormtroopers): https://501stlegion.org
• The Georgia Gems (Steven Universe)  https://m.facebook.com/thegeorgiagems/