For hard mode, I could really only find sequels in series, but here are a few suggestions: Andre Norton - Warlock of the Witch World; Michael Moorcock - The Weird of the White Wolf
My card: Max Gladstone - Full Fathom Five (I've been meaning to read the Craft Sequence series anyway.)
My card: Shalini Abeysekara - This Monster of Mine
Suggestion: Anne McCaffrey - Dragonriders of Pern; Mercedes Lackey's Dragon Jousters series or any of the Heralds books from Valdemar; Rebecca Yarros - Fourth Wing
My card: using the first suggestion for this square, Naomi Novik - His Majesty's Dragon
Suggestion: any LGBTQIA+ romance, such as TJ Klune - Under the Whispering Door (or pretty much any other book by this author)
My card: TJ Klune - Wolfsong
Suggestion: Nghi Vo - The Empress of Salt and Fortune; Laini Taylor - Daughter of Smoke and Bone
My card: Barry Hughart - The Chronicles of Master Li and Number Ten Ox (omnibus)
My card: Katherine Arden - The Bear and the Nightingale
Suggestion: any anthology, especially any edited by Ellen Datlow (books span multiple genres)
My card: Ellen Datlow, ed. - Mad Hatters and March Hares
Suggestion: Samantha Shannon - The Priory of the Orange Tree; Anthony Burgess - A Clockwork Orange
My card: Jostein Gaarder - The Orange Girl
Suggestion: Joe Haldeman - The Forever War
My card: Poul Anderson - The High Crusade
My card: Michelle West - Wild Road (est. releasing this month to Patreon backers)
Suggestion: virtually anything by Jane Austen (so many movies/shows/plays); Gary K. Wolf - Who Censored Roger Rabbit? (warning: not nearly as much fun as the movie Who Framed Roger Rabbit?)
My card: Jane Austen - Persuasion
Suggestion: John Wiswell - Someone You Can Build a Nest In
My card: Paolo Bacigalupi, Tobias S. Buckell - The Tangled Lands