As has been pointed out before many 'storygame' mechanics appear in older 'trad' games like Toon, Ghostbusters, James Bond, etc. Hardly surprising as narrative games and storygames didn't come out of nowhere but are inspired by previous game designs.
Sometimes the procedures used in trad RPGs are essentially narrative systems too. Players don't always recognise narrative procedures as "mechanics" per se, because they emerged from gameplay experience rather than a rulebook.
For example, probably half of the
Call of Cthulhu players that I've gamed with generate a "backup PC" to run if/when their character dies or goes mad. Backup PCs are treated as "minor NPCs with shared player/GM agency" until replacement. This ensures they're already integrated with the story, and don't just materialize out of nowhere when the original PC dies. From my perspective, this is a narrative mechanic.
When I originally started playing
Burning Wheel, I realized that most of the Artha mechanics were just codifications of roleplay processes that were already natural to me in trad gaming. I recall several years ago in an RPGnet thread, the designer was confused that as a player I wasn't approaching BW differently from a trad RPG. Ironically, the parts of BW that
didn't feel intuitive to me were task-res systems like positioning and scripted combat.