Traitor Guard List Help

Hi guys! I have some cultists and traitor guard I want to run as a traitor guard hold out army. I was also thinking about using a leman russ as a stand in model for the chaos predators.

What else should I run in this list? I have access to the following things:
\- helbrute
\- defiler
\- chaos knights
\- heldrake
\- normal thousand sons stuff

I was also looking at the chaos cultist detachment, but what 1dp would you slot in to help things?