Fiction writers, at least in their braver moments, do desire the truth: to know it, speak it, serve it. But they go about it in a peculiar and devious way, which consists in inventing persons, places, and events which never did and never will exist or occur, and telling about these fictions in detail and at length and with a great deal of emotion, and then when they are done writing down this pack of lies, they say, There! That's the truth!
Ursula K. Le Guin, Introduction to The Left Hand of Darkness,
Ursula Le Guin has left us, and she will be sorely missed. But she's survived by a whole host of brilliant fantasy and science fiction writers. In her honor, here's an incomplete list of living women writers whose work I think deserves your attention:
Ann Leckie, whose debut Ancillary Justice is probably the most brilliant SF novel I've read in the past five years, and examines (among other things) the social construction of gender, the nature of artificial consciousness, and the impossibility of consensus in distributed systems. You can read two of her short stories, "She Commands Me and I Obey" and "Night's Slow Poison", online for free.
N K Jemisin. I've heard only good things about The Fifth Season, but the book of hers I've actually read and can recommend myself is The Killing Moon, which got me interested in high fantasy again after having decided I was done with the genre.
Catherynne M Valente, who writes so much that I cannot possibly keep up with it. I'm a sucker for short story collections, and she has the format down to a fine art; if you can get your hands on a copy of The Melancholy of Mechagirl, don't hesitate.
Susanna Clarke hasn't written a lot, but every word of it is magical. As a masterpiece of fantasy worldbuilding, Jonathan Strange & Mr Norrell bears comparison with Tolkien and Gormenghast.
Margaret Atwood. Although Atwood may prefer not to call it by that name, she is a master of science fiction, and has been since at least 1987, when her novel The Handmaid's Tale won the very first Arthur C Clarke Award. I'll let Le Guin herself give you a review of Atwood's more recent work.
You might also enjoy reading Le Guin's contemporary Joanna Russ and her predecessor James Tiptree Jr (the pen-name of Alice Sheldon), each of whom had her own distinct vision of what feminist science fiction could be.