Help with gametypes

If anyone could tell me how to get gametypes like HaloBall, Rocket Race, and I’m not sure if there are any more, PLEASE let me know.

Play them in Matchmaking, and then save the game variants out of your Temporary History.

This also works for updated gamtypes, i.e. Infection with Alpha Zombies or Zero Bloom Slayer (since the changes are contained in the individual game variant files).