Resources I find useful.

Gaia Threads

The Color Scheme Guide Compilation Thread by Zeetheus
The New Color Scheme Guide Compilation Thread by emetology
Visual Color Scheme Guide! by DawnLuna

Taking the Scenic Route: A Scenic Guide & Catalog by Khenarthi
Lighting Mod List by hiimbeary
Background Cutter Items by Aerdian
Avatar Tricks: Foreground Cutting by Aerdian

Make-up & Facial/Muscle/Bust Definition by ElegantlyLuminous
scissors + misc mods list (clothes, haircuts) by emetology
Bewere/Cheshire/SurgicalScissors Cutter Mod Item Guide by Aerdian
The Ultimate Hair Guide v2 by LayDeDeadpool

How to Make a Good Avi - Some Observations by 0ri0

Challenge Resource/Inspiration Thread
The Every Evolving Item Challenge - by Katolincat