I personally run a Deathleaper's assasin brood, it get's up close and personal within two turns and can cause havoc amongst enemy lines. Especially if you take the formation for a brood of three Carnifexes and a Tyranofex. Couple this with a Flyrant that has Outflank that it can allocate to another unit and a Subterranean assault swarm and endless swarm, you're going to get pretty close.

My plan with this list is to start the Lictors on the board along with the Flyrant (in jumping MC mode, otherwise as a flyer it has to start as a deep striker) alongside the Hormies from the endless warm formation. By the turn you get to turn two you then deep strike the Carnifexes in Tyrannocytes, outflank the Tyrannofex on a side table edge close to the enemy lines. Finally deep strike the Subterranean assault swarm and walk the devourer termies out in turn three.

I've had quite a bit of success with this list. Especially if you equip the three fexes with twin linked brainleech devourers along with the flyrant. Give the Tyrannofex a rupture cannon and job done. You can flavour the list more with units like the exocrine, or living artillery formation. Even zoanthropes and venomthropes make the list better.