Here is my list that has had a good amount of success in 8th edition so far. I'm looking to bring it to an upcoming ITC Tournament. It's 2,000 points exactly.
BATTALION DETACHMENT
HQ
Farseer {Guide, Doom} – Singing spear [120]
Warlock {Conceal/Reveal} - Witchblade [37]
ELITES
Solitaire [117]
Mandrakes (10) [190]
TROOPS
Guardian Defenders (20) [160]
Kabalite Warriors (10) – Blaster, splinter cannon [100]
*Raider – Dark lance, shock prow [116]
Kabalite Warriors (10) – Blaster, splinter cannon [100]
*Raider – Dark lance, shock prow [116]
FAST ATTACK
Reavers {Painbringer} (6) – Agoniser, 2x grav-talons [194]
Hellions {Adrenalight} ( 8 ) – Splinter pistol and agoniser, phantasm grenade launcher [143]
HEAVY SUPPORT
Dark Reapers ( 8 ) – Tempest launcher [295]
Ravager – 3x dark lances, shock prow [156]
Ravager – 3x dark lances, shock prow [156]
The Dark Eldar and Harlequin (Solitaire) units stick with Power From Pain and Rising Crescendo, while the Eldar go with Soul Burst as Ynnari.
I place my reapers in an isolated corner of the map with decent visibility. Surrounding them is a large block of Guardians to bubble protect from deep strikers. In the middle of the two units is the Warlock to cast conceal 3" and a Farseer to cast guide on the Reapers until enemies are close enough for Guardians to benefit from it. The Solitaire will likely be hiding nearby to counter charge anything that comes close. He also loves any opportunity to charge a Doomed character, so having him close to the Farseer is key. The Farseer is also my warlord.
Kabalite Warrior gunboats have three purposes. 1. To soften up units before the Hellions, Reavers, and Mandrakes charge in. 2. Charge with their shock prows to soak overwatch before the Hellions, Reavers, and Mandrakes charge in. 3. Fly around and steal objectives. The Ravagers also fly around and steal objectives, but they do it while pointing dark lances at big things.
Last but not least is the Mandrakes. This is by far my favorite unit in the army. They are unbelievably versatile and play an amazingly reactive role in this list. They are fast, defensiveish, strong in melee, good at shooting, and can even scare vehicles/monsters with mortal wounds (not ideal targets, but viable). Normally, I deploy them turn 3 to benefit from the rerolling charge level of power from pain. They either join their impetuous Drukhari brethren in melee glory, find a nice shiny objective to steal, or support the Reaper/Guardian/Farseer/Warlock bubble against pesky intruders.
Would love to hear what you all think and happy to answer any questions or concerns! Thank you for reading!