Fey Magnet

Fey Background
Being in the fey for so log causes one to have a sense of direction to anything fey. Almost like a magnet, being able to sense anything fey nearby, or an intense fey sense further away.
Must have a strong connection to the Feywild itself. It is not enough to have fey ancestry. 

 Passive Sense
You can sorta passively feel the aura of fey things, the stronger connection something has to the Feywild, the stronger the aura. In theory you can detect something infinitely far away, but the further away something is, the weaker it gets, until you no longer can detect it.

Things that strengthen something's fey aura could be things like; recently been to the Feywild, having Fey Ancestry, having Fey Teleportation, being Fey Touched, or being Feylost.

To begin with, at level 1, you might be able to sense someone fey in the same building as you. And someone who've just left the Feywild you might be able to detect if you're in the same city.
Each level adds another mile to the sense. As well as at levels 5, 11, and 17. where you gain 1d4 miles instead.

Meditating on it like a spell
This sense isn't very precise, the closer you are to the source of the fey aura, the clearer you feel it.
As well as that, you can also meditate with this sense, to use it sort of like Detect Magic. Where you can see as far as before, but adding a Wisdom ability check to the strength of your sense. Making it reach farther and clearer.

A lot of this has been left open to interpretation, so that the DM can bend it to fit scenarios.