This is by no means a comprehensive list, and links are presented in no particular order:

MAGAZINES
KitBuilders
Amazing Figure Modeler
Nightmares In Plastic
Fine Scale Modeler

FIGURE KIT PRODUCERS/SUPPLIERS
Artomic
Geometric Designs
Solarwind Productions
Resincrypt
Amok Time
Monsters in Motion
X-O Facto
Model Giants
Nocturna Productions
Forbidden Zone
Lunatic Fringe
Monarch Models
Model Prisoners
Dark Carnival Models (requires password)
Jimmy Flintstone
Resin Realities