Keyan Farlander (EU) / Evaan Verlaine (Canon)
It was relayed by Steve Sansweet, former Head of Content/Fan Relations at Lucasfilm, in the "Ask the Jedi Council" feature on the old Starwars.com website that the identity of the Y-Wing pilot was canonically unknown but highly likely to be Keyan Farlander, a character introduced in the LucasArts game X-Wing.
Possibly of more interest is that other pilots survived, just off-screen.
Q. In Episode IV after the Battle of Yavin there are four ships: Luke and Wedge in their X-wings, Han in the Falcon, and a Y-wing
fighter. Who was in the remaining Y-wing ship?
A. It's pretty definite that more than just those four ships survived from the Alliance attack on the Death Star; others just
aren't visible on screen. The Y-wing pilot has never been definitively
identified. But, if you're the gambling kind, I'd say the smart money
is on Keyan Farlander, a starfighter pilot introduced in the original
X-wing game from LucasArts. Back in 1992, LucasArts published a
novella starring Farlander that came with some copies of the game. The
strategy guide for the game continues that story and places Farlander
aboard a Y-wing fighter during the final assault on the Death Star.
Farlander survives the battle, making him a good candidate for the Y-wing pilot seen at the end of the film.
In more recent years (and canonically), the pilot now appears to be Evaan Verlaine by a simple process of elimination. We know from the new Galactic Atlas that she was part of Gold Squadron piloting an Y-Wing. Of the named pilots, we saw all of the others (Dutch, Pops and Dex) killed on screen.
This doesn't account for the missing Y-Wing pilots led by Dutch (of which there were eight) but it seems highly unlikely that a non-named pilot would have been the one seen to have survived.