The Regalia in Forza Horizon 3
First up is a fairly recent cross-over. Players of Forza Horizon 3 who also happen to be Final Fantasy XV fans got quite a treat. The Regalia is a familiar sight to any Final Fantasy XV player. Starting August 1, 2017, the Regalia was added into Forza Horizon 3. It makes this list for two reasons. First off, a vehicle from a role-playing game making its way to a racing game is strange. But also, fans of Forza Horizon 3 really just want more real cars in the game. No one asked for this cross-over and many don't really care, so why was it added? Nevertheless, you can drive around the Regalia in Forza Horizon 3 for free, if you so choose.