Your game modes aren't deleted. You can just select the modes in the more generalized playlist.

So for example, tactical slayer is under quickplay. There's even an option for just bandit/br starts.

BTB heavies is under the big team battle playlist.

Etc. Etc.

There are also some game modes that haven't been in rotation for awhile available to choose from.

Edit: I don't know where game mode "x" is. The general playlists are Big Team Battle (12v12), Squad Battle (8v8), Infection, Rumble Pit (FFA), Quick Play (4v4), Doubles (2v2), then firefight and ranked. If you're looking for a specific number of players, look there.