I am pretty sure this was 3.5 era; if someone remembers what it is and it turns out not to be, mea culpa entirely.
The detail in question is a fairly senior female martial NPC whose trophy room includes the three heads of a chimera mounted on a wall and the skull of a half-fiend hill giant with a sword still embedded in it.
I'm interested in what meta-level, as it were, people are most drawn to implementing new character concepts, on a scale ranging from new base classes with new mechanics (like oracle revelations or ki pools - is there a generic term for pools of resolve and panache and grit and so on?) to prestige classes to just making the concept distinct by a particular set of interlocking feats. In a context of "here is an interesting new sort of character to roleplay" rather than "this would let me minmax in new ways".
I'm particularly interested in reasoning behind, given that any new concept adds some more optional complexity to the game, which of those or other levels works best for you as most efficiently managing that complexity.