Tracker art consistency a bit weird ?

I was trying to make one of my banners look a bit better and ran into some confusion. 

You can see the dude i was trying to copy here : https://imgur.com/a/Pulp8v8
What i found weird is how i don't have this specific tracker art he uses here available to purchase yet i have a bunch that look quite similar for other legends, seeing as it depicts default wraith (if I'm not mistaken) i feel like it should be a cosmetic that's available to buy whenever , no ? What I'm trying to get at is that i don't understand which ones are available to me and why , i feel like it should be clearer.

That could easily be a misunderstanding from my part because i am coming back to the game after not having played for 7 years but i feel like i wasn't explained that info.