Seeing the patch in the photo, you may ask “what is a three percenter?” The narrowest definition is that three percenters are hard-line gun owners who are done backing up and will not comply with more infringements of their right to bear arms. A broader definition would be that they are hard-line Americans who are done backing up and will not comply with further infringement of any of their rights. It also alludes to the three percent of the colonists who took to the field against the King during the Revolution, and the estimation that at least three percent of modern Americans will actively fight, if it comes to it, to preserve liberty. Read this essay for more explanation.
Oath Keepers and Three Percenters are separate groups, but it is not a surprise to see people who consider themselves both an Oath Keeper and a Three Percenter. If you read the supplied links you will see why.