I made most of the badges on Credly--a website that allows users to create, award, and claim credit for different competencies. I decided that these "credits" achieved my image of a digital badge.
from a screenshot of my "Created Credits" on Credly
Blackboard has an "Achievements" option. I use this to assign my students badges when they have met all of the requirements for the visual analysis essay, for instance.
Because I don't really use points or percentages when I grade, this gives students something tangible to understand where they stand in the course.