The new Death knight spells in Battle for Azeroth are Thoughtsieze and Death’s Advance.
New Death knight Spells:
In the 8.01 Beta Build there aren’t any new DK spells, but this is just the first beta build.
Check out the detailed Spell changes in this wowhead post ==> http://www.wowhead.com/news=281090/battle-for-azeroth-beta-25902-class-spell-changes
We don’t expect major changes in the DK gameplay for the new expansion, because the three DK spec are quite diverse.