We are away for christmas and have just finished 2 games.

Dark Elfs totaly crushed Wood Elfs and Lizardmen beat Orcs pretty easy.

We didn't being all the FAQ and rules and the internet access is limited where we are (we didn't expected that)

So a stupid question because to build an Undead deck for the first time without the rules is a bit of a challenge.

Is there any abilitys or keywords for Undead or Vampire?

The Undead capital says to discard the top 5 cards at the start of the game.

Is it just necromsy or there some other way to benifit from the cards in the discardpile in a general way?

Necromancy and cards that benefit from cards in discard pile (Abyssal Terror for example).