Aliens vs predator, not on the list.

Try making a thread like this in support.

You can write a ticket, asking for it to be put back on the list. They might do it for you - they've done it for me in the past with the London 2012 Olympics game.

The ticket problem is that it may take months, and I need to create giveaways for the month of January for my groups.
:(

Alien vs Predator is no longer on Steam so been removed from the list. Your only choice would be to contact Support.

Happens every time a game is removed from Steam, they end up manually adding them back to the list. IIRC that and A:CM were removed on the 30th or so, with New Years it might be a few days but they should be back on the list soon.