So I'm trying to come up with a few Ribbons, and I'm not 100% sure how they work.

I know that they do not give any kind of bonus to combat, but can they grant new skills? Or change previous skills? What about tools? Or is it just a "here's a cool thing you can do that has no bearing on anything"?

The only two features I know of that are specifically referred to as Ribbons are Thieve's Cant and Storm Guide. Are there any other specific examples out there?

Thanks!