Halo 3: Mythic Required Mythic Required Heroic Required No DLC Required

Ranked
Lone Wolves
Team Slayer
Team Throwback
Team SWAT
Team Snipers
Team Doubles
Squad Battle
MLG

Social
Rumble Pit
Social Slayer
Social Skirmish
Multi Team
Social Big Team
Action Sack
Team Mythic

Double EXPs
Grifball
Team Control
Team Flag
Social Living Dead

And Bungie's patch notes from the update:

Those without the latest and greatest map packs looking for more love should be happy to hear that we’re opening up Team Slayer for everybody. Those with all the new stuff looking for some more Mythic make out sessions should find some playlists to cuddle up and spoon with as well.

Details, girlfriend:

Ranked:
Team Slayer – All extra content optional (Includes Heroic, Legendary, Mythic, Mythic 2 and Cold Storage)
Team Throwback – Weighting on Valhalla, Standoff reduced. Weighting on Heretic, Citadel increased. The Pit replaced with Pit Stop.
MLG – Maps updated to MLG version 7. Guardian and Lockdown (Foundry) removed. Heretic added to Slayer, Oddball and CTF. MLG is now Halo 3: Mythic required.

Social:
Big Team Mythic – Removed.

7 on the 7th:
7 Player FFA on Cold Storage, Assembly, Heretic and Citadel. (Halo 3: Mythic required)