Easy for me, it would be an oldtimer "trappers model" pocket knife. You know the type three blades none of them locking.

Reason, an uncle of mine carried it for 20 years or so and my aunt gave it to me after he died in the late 1980's. I carried the knife as an EDC for a long time, and even today I will sometimes carry it, usually if I am going to be in the company of sheeple

If you included swords in the list then the oldtimer would be the second last to go.

I have an old wall hanger sword that my grandmother cherished and she gave it to me one Christmas when I was 14. Nothing special about the sword it's just that it was a cherished possesion of hers.
Come to think of it I am not sure that sword is really mine any more as it has spent the last two years or so hanging in my oldest daughters bedtoom.