[hippypancake]

Lictors would work well, ravenors, and trygons could also work as they could be burrowing guys that stay underground

Fluff-wise for a HQ maybe take a Tyranid Prime and just make it look like a giant broodlord? it could be a really cool conversion job.

Sadly when the new codex came around I dropped my genestealer spam army so idk much about the rule now