Put some nice Ash waste effect on it and maybe the odd skull or two.
You have one nice army there. I would add another 2 monoliths to that and a few more warrior squads. Are you able to replicate the paint scheme of the monolith yourself? The one that was linked by
Celephus Drax has a different colour scheme (and there is only 1).
Oh, and I like the old school Necron Lord. Stick him on a base though.