If you are looking for the massive list of car packs (like the Mobil 1 or Rockstar packs) found on Xbox One, they for the Xbox 360 version. Turn 10 officially stated that DLC was exclusive to the Xbox One version.
standalone expansion, which was released as a separate game entry rather than traditional DLC for the main title. Forza Horizon 2 Dlc Xbox 360 Rgh
Adds over 100 cars from Forza Horizon 1 and the Xbox One version of FH2 . If you are looking for the massive list