When you ride on the Regalia in Final Fantasy XV, you'll notice that it has a music player. This allows you to listen to different Final Fantasy soundtracks that have been used since the first Final Fantasy game. Some of the songs are already playable when you use the Regalia.

Songs which are already played when you drive the Regalia include Memories of FFI, FFVII, FFXIII, FFXV Original Drive Music, FFXV Afro Jack, Justice Monsters V, and Kingslaive.

Memories of FFII can be found at the Longwythe Rest Area in Leide. You'll have a total of 11 songs which include The Rebel Army, Castle Pandemonium, Chocobo Theme, and Tower of the Magi.

You can buy the Memories of FFII at the Coernix Station. Just find the Alstor shop in Duscae to get it. The soundtrack for FFIII is longer than that of FFII as it has 13 songs in it including the Boundless Ocean and Aria the Maiden of War.

If the FFIV soundtrack appeals to you, then you can acquire it from the Hammerhead Outpost shop in Leide. This soundtrack has an ethereal theme to it including the Tower of Zot, Theme of Love, The Airship, and Another Moon.

The Memories of FFV soundtrack is also in Leide and can be found at the Galdin Quay shop. If the FFIV soundtrack sounds romantic, this one sounds catchy and danceable with titles that include Mambo de Chocobo and The Dawn Warrioirs.

Memories of FFVI is sold in the Taelpar Rest Area in Duscae and has some interesting titles in it including Searching for Friends, Dancing Mad, and Battle to Death.

Memories of FFVIII can be bought at the Hammerhead Outpost in Leide while Disc and and 2 of the Memories of FFIX is available at the Coernix Station at the Cauthess shop in Duscae.