These six websites are LOADED with great tools and information.  If they aren't bookmarked in your browser yet, they SHOULD be!

www.foldfactory.com

Trish Witkowski (self-described “Folding Fanatic”) is the driving force behind this creative informational site. If their handy InDesign plug-ins don’t interest you, maybe their YouTube Channel will.  It's full of creative ideas for custom folds that can make any of your design pieces standout from the pack.  They even have additional Fun Fold Facts available to impress and inspire you.