While working on Steinhardt's Guide, we're also making some additional content on the side, notably Legends of the Roundtable.
This is a book that's all about the legend of king Arthur and gives it a fun twist by allowing Morgan to win unlike in the classic story. One of the most well-known figures in that legend is the lady of the lake. Funny enough, if you take the setting in a futuristic era like Eberron, you could call her the Artificer Patron and it would work just as well.
(Dungeons and Dragons 5e Subclass)