We don't really have a big guide or anything, but here is a list of topics people might find interesting since a few of them are getting buried under newer stuff.

Useful Knowledge

• Beginner's Guide? Tips and Q&A
• Tips & Tricks from my JP experience
• Best place to farm X?
• Equipment upgrading strategies
• Tips & Tricks on FKG - Be enlightened or teach us your ways
• Effectively Using Equipment
• Wiki FAQ Page

PSAs

• About Raid Bosses... (i.e. stop going ham on other people's bosses)

Serial Codes

• Wiki serial code page
• Campaign Threads
  
  • Astra Galus
  • Free Rainbow Skillbloom Giveaway
  • Anime Expo Code
  • MMOsite Anniversary Codes
  • Violetta Tulip

Events

• Wiki event page
• Event 42 - The Ghost of Garde
• Event 41 - Witching Hour Tricksters
• Event 40 - Merrymaking in the Cool Forest Breeze
• Event 39 - The Blue Sea Demon
• Event 38 - Summer Beach Vacation
• Event 37 - The Shining Milky Way Crossing
• Event 36 - The Sea, the Bride and the Legendary Bouquet
• Event 35 - Pitter-Patter Raindrops in the Forest
• Event 34 - The Quiet Lake Borders
• Event 33 - Bestirring Ramp Rally
• Event 32 - The Day the Whale Swam in the Sky
• Event 31 - The Ancient Tomes: Festival of Skane
• Event 30 - The Cherry Blossom Battlefront
• Event 29 - A Dance of Change in the Spring Breeze
• Event 28 - The Lady from the Flower Capital
• Event 27 - Love Knight
• Event 26 - Splendor Festival Grande Fleur
• Event 25 - Aim for the Top!
• Event 24 - Bells Ringing in the Eve of the Sacred Night
• Event 23 - For the Flowers of the World, With Love
• Event 22 - The Mountain, The Maple Tree and the Glutton
• Event 21 - Winter Cheer
• Event 20 - Adventures Under the Full Moon
• Event 19 - Fortune Comes to the Merry Flower
• Event 18 - Christmas Festival
• Event 17 - The Fos Hunting Festival
• Event 16 - The White Shadow of the Ancient Residence
• Event 15 - Heavenly Flower Festival
• Event 14 - The Great Parade of the Ghost Pumpkins
• Event 13 - Drops of Desire Glittering in the Sun
• Event 12 - Operation: Enemy Subjugation!
• Event 11 - When You Wish Upon A Star...
• Event 10 - Thoughts Hidden in the Palm of Her Hand...
• Event 9 - The Flower That Dances in the Night!
• Event 8 - A Friendship Worth Fighting For
• Event 7 - Prosperity Festival - Phosphorescence Carnival
• Event 6 - Restore Peace to the Kingdom
• Event 5 - The Lingering Scent of Ancient Flowers
• Event 4 - In the Glow of the Night
• Event 3 - The Power of the King's Adviser
• Event 2 - For the Sake of Our Precious Memories
• Event 1 - Bremen: The City of Ruin

Miscellaneous

• Friend code thread
• Compiled Friend ID list of Forumers
• Salt thread
• General chat thread
• Garden appreciation thread
• Archive of affection scenes
• FKG Lore Discussion
• Affection scenes
• DMM thread

External Resources

• Japanese wiki
  
  • List of all DMM version flower knights and event girls

If anything is missing just reply and I'll add it to the list.