The Nabi Nabi no Mi, or the Navi Navi Fruit (I think you know where I'm going with this).
This fruit literally makes the user incapable of being lost, turning the user into a Human Compass (人間の羅針盤, Ningen no Rashinban).
Upon touching a geographic location, the user immediately receives all the possible pathways and subsequent prominent places that it contains, such as the villages or the kingdoms of that specific island, hidden or otherwise. The pathways manifest as highlighted footsteps on any surface that only the user is able to see.
It doesn't highlight which path is the safest, so a path can be very short and convenient but have lurking traps and ambushes that can kill you.
It's bound to cause immense information overload for an untrained user of course, but with a sufficient amount of training, the Nabi Nabi no Mi can become one of the most clandestinely powerful non-combat DFs on the right user.
Imagine the user learning how to use Moonwalk, or wearing slippers made out of that 100%-buoyant-wood-I-forgot-the-name-of, and the user steps on the sea itself. Bam. All possible routes shown can indicate any nearby islands, and although it's a stretch, even Raftel itself. (But that renders Poneglyphs unneeded, so I think this will be that one exception to the rules of this DF).
Potential awakening ability can include the user seeing every "path" out of "everything", or more specifically, all the possible "solutions" to any "problems" they have touched upon.
Weaknesses? First, I think it's like how some SMILES aren't able to turn off their animal counterpart, the user is unable to turn off their devil fruit powers, i.e. they're always seeing highlighted footsteps everywhere! Unless they're sleeping and have their eyes closed. This makes it an only-user problem and can be an inconvenience to the user. Secondly, the daily information overload they receive in their brain after waking up is no doubt unpleasant. Imagine opening your eyes only to be bombarded by numerous glowing footsteps that appear from your bed to outside the door that leads everywhere. That's going to sour your morning, for sure. Third, the user can be immediately subdued by blindfolding them first, since that way, they'll be unable to locate how to get out of their situation. Apart from that, the user is affected by standard Devil Fruit weaknesses.
So... what do you think of this hypothetical Devil Fruit?