From publisher blurb:
Lana's Fateful Vault is a splash guide for 5th-Edition Dungeons & Dragons. It is part of Nat19's "5.19th Edition", which is reverse-compatible with 5th-Edition, and introduces new and exciting elements to the game. This splash book features content centered around Somnus Domina's goddess of fortune and temptation, Lana, Duchess of Fortune. Its content follows themes of love, friendship, lust, temptation, luck, and fortune.
Below is a quick run-through of what can be found within this 50+ page guide:
Lore about Lana, her divine realm, and followers
15 new subraces + new Legacy Traits
16 new subclasses
11 new spells (and several spell re-inclusions)
8 new creatures, including an aspect of Lana and a mech
6 new magic items, including two artifacts
7 new elixirs
Phantom Third, a dice game that emulates games like poker, which is easy to play in and out of character.