Hellflayer Chariots of Slaanesh
Also called "Scented Harvesters", "Decadent Reavers", and "Shred-chain Sisters", even while techincally they are just oversized mowers fluff-wise.
Slaanesh takes a great deal of pride in his/her realm within the Warp, as he does everything else. Unfortunately his/her "brothers" are always fucking up his lawn. Crystals, feathers, and traps (the bad kind) left all over the fluffer farm. Blood and guts plus some guy's lost skulls left strewn all over the walkway. Even his fellow gardener can't seem to keep slime and insects from getting into the Purple Prince's PCPetunias. So what's a supreme ruler of creation to do? Wank/Shlick some gardeners into existence of course!
Hellflayers were a design similar to Slaanesh's existing cavalry forces of chariots, but with an extra large thresher in the back for grinding to pieces anything left after a battle so Slaanesh's carnivorous plants could consume it and leave his gardens like Willie Wonka's acid trip again. The Daemonettes selected to conduct this task were invariably the ones who had gotten on Slaanesh's bad side (although not to an extreme degree) as without any souls to consume or emotions/physical feelings to feed on and with only drudgery to do, the task itself is a deadly proposition as a bored and unhappy Daemonette can begin to fade from existence.
Eventually two Daemonettes that were sentenced to the task decided to subvert their creator's orders, and took their gigantic tool (not THAT kind) for a joy ride DURING a battle rather than after it ended, slicing Nurgle's Daemons to giblets while they were still moving. They drove through the ranks of the invaders and the punished pair were splattered with gore as they experienced an orgasmic height of joy no Daemonette had ever before felt as the pain and fear felt by the foes of Slaanesh passed through the metal as the ultimate drug effect which strengthened them until they were moving so fast that light could no longer reflect off them, rendering them invisible.
Slaanesh is a highly emotional Chaos God, prone to extreme mood swings with a wrath as vicious as Khorne and a gaiety and affection (no pun intended) that rivals Nurgle. His pleasure at the effects made it so that henceforth (wo)manning Hellflayers no longer was a punishment but the ultimate reward. His terrible anger at the pair that had dared subvert his command had him transform the two Daemonettes into unfeeling marble statues at the start of the walkway to his palace with their backs turned permanently away from Slaanesh's glory.
On The Tabletop
A more expensive Seeker Chariot with the ability to increase the number of Attacks the leader of the two crew gets as it deals more Impact Hits. A superior hammer, but a bigger points sink and as a result more likely to be cannon-bait. Not really better or worse enough to recommend above them, just be aware that you're putting another egg into the same basket.
A chariot that deals D6 Sx2 (so S8 or S10 with a Herald nearby) AP-1 D1 attacks after the regular attacks but without any Hammer of Wrath hits...or any special rules whatsoever apart of the regular Slaanesh Daemon special rules.
Same case as Warhammer Fantasy, although it got a nice and juicy buff to its offensive power. While something to consider in a monotheist Slaaneshi army, a mixed-Chaos God army will still have these as a decent option whereas Seekers and Seeker Chariots tend to be secondary choices.