Thats fair, but when I had asked for examples for Tiefling for example (my own personal issue, I cant get over what 4e did lol) I was given this list of things which...remove the 'I now look like your stereotypical Devil but i'm not I promise!' was just stuff that can be ANYONE's back story.
I get it though, and please dont feel I'm harassing you personally, everyone has their own preferences and what attracts them to various aspects (sp) of a game or setting.
The issue with that approach is that you could say the exact same about any race.
Take out "I'm an elf" and you could have anything have that same backstory. Maybe with smaller numbers if you are one of the few actually utilizing their extended lifespan, but dwarves, gnomes, and a few other races also have those extended lifespans.
Sure, anyone can have the backstory that their bloodline was tainted by the presence of evil, manifesting itself in inherit powers and whispers in the darkness of their soul. But Tieflings are that trope, and looking for "what can I do beyond that that is not able to be done by any other race" is relying on the DM to do that heavy lifting.
For Example, I took them for my homebrew world and said that during the destruction of the human's original world by the Great Old Ones, the Tieflings lost faith in the Gods who had stopped responding to their prayers, and turned to dark powers to try and save their kingdoms. They actually had a unique religion, not worshipping the gods, but instead worshipping the "Lost Legion" a military unit that had held the line as humanity retreated through the Gate that led to this world, sacrificing their lives for the safety of humanity.
That isn't the initial design of Teiflings, but it plays in the same space, and shows that it falls to us to design things if we want more than just the generic tropes.