Greater Shaderavens ect

I am currently in the middle of writing a custom codex (and it is highly addictive!) Im not doing a complete overhaul, just some points adjustments, wargear changes and overall going with the theme of more options and less constraint.
Im also in love with 40k lore in general.
With that in mind im looking to add more variety of models to the Court of the Archon. I've already added Dracons and Mandrakes but one want to expand into other creatures mentioned in the lore like Greater Shaderavens with their maddening caws, and the worm-like haemovores.
Does anyone have any fun yet balanced ideas for these two (or any other ideas for creatures mentioned in the lore that you think should be in the court?)