Unlike modern "live service" games, the DLC for FH2 on 360 is static. Here is the complete library available for RGH install.
While technically not a DLC for the main game, a standalone expansion titled Forza Horizon 2 Presents Fast & Furious was released for the Xbox 360. Nature of Content Forza Horizon 2 Dlc Xbox 360 Rgh
This guide explains what content is available, how to install it on a modded console, and why most "DLC lists" you see online actually apply to a different version of the game. 1. The Harsh Reality: DLC Availability Unlike modern "live service" games, the DLC for