I don't know, but I would nominate Crips, Bloods, MS-13, Asian gangs, Hispanic gangs, prison gangs, and organized crime families in general for starters.
The "oath" ... must have an official definition somewhere. Like you, I have personal thoughts about domestic enemies.
If you search the web for domestic enemy, DU pops up first with their definition, yuk, and then there is a military site with the different oaths for each branch and the guard & reserve.
"I,____________, do solemnly swear (or affirm) that I will support and defend the Constitution of the United States against all enemies, foreign and domestic; that I will bear true faith and allegiance to the same.
But I suspect we the people, haven't used this charge officially since the Rosenbergs.