Limited use so far, I think the materials need to include a plethora of suggestions (with specificity) to get more use out of this mechanic.
There are the general categories one can go with, to adjust specifically to the character:
2. Race (maybe too broad though for some, e.g. Hyborian?)
3. Nation (or smaller subset, e.g., village or tribe)
4. Organization (mercenary company, gang of thieves, guild, sorcerors' "ring", pirate crew, city guard, etc.)
That probably is some overlap with the book.