Similar to the Ravenloft Character Backstory Thread, this thread is to share your favorite mechanical combinations using the official races for Ancestral Lineage, Gothic Lineages, and/or Spirits Bard or Undead Warlock subclasses from the book. I've got a few:

1. Dhampir Kensei/Ranger/Fighter Build - Simply put, if you want to make the most out of your Vampiric Bite attack, this is the way to do that. You can check out the other post for more details. 
2. Reborn Hollow One Artificer (any subclass works, but I particularly like Armorer for this build) - Reborn get advantage on death saving throws, Artificers can replicate both a Cloak of Protection and Ring of Protection, both of which add a +1 bonus to all of the attuned user's saving throws, and their level 20 capstone ability grants them a bonus to all of their saving throws dependent on the amount of magic items they're attuned to (up to 6). If you combine all of them, you get a +8 bonus to your Death Saving Throws (effective +13 to Death Saving Throws), advantage on them, and if you get a 16 or higher, you come back to consciousness at 1 hit point. 
3. Hexblood Warlock (any subclass works, but Archfey fits thematically, and Hexblade is great if you want to annoy your party by being a "Hexblood Hexblade") - As a character that has played a Changeling Warlock, I know the pain of being a low level Warlock that only knows two spells and has only one or two spell slot(s) at any given time. Hex Magic would effectively let you know twice as many spells (including hex for free!) and lets you cast the spells more often. 
4. Hexblood Monk - Monks get the most attacks earlier than any other character option, and Hex benefits the most from having a ton of attacks. Bonus points if your party's Artificer, Sorcerer, or Wizard casts Haste on you, and if you have an Eldritch Claw Tattoo. 
5. Undead Warlock/Conquest Paladin Multiclass - Form of Dread and Aura of Conquest work very well together when combined (cue maniacal laughter). 
6. Eladrin Spirits Bard/Wild Magic Sorcerer Multiclass - If you want to be as random as possible, this is the way to do it. Eladrin come in 4 different varieties that you can determine randomly at a long rest, Tales from Beyond is random and tied to your Bardic Inspiration die, and Wild Magic is the most random mechanic in the game. Your party will hate you, you will hate your character, and your DM will forever ban you from their table. What isn't there to love? (In case it wasn't clear, this is a joke. I do not condone this build or players who play builds like this. Play at your own risk.)

Does anyone else have combinations that they like? I'm excited to see what you come up with.