Few things hit the spot quite like a good sapphic Victorian story—the repression, the stolen glances behind fans, the whole society-on-the-brink-of-modernity tension. For a foundational pick, Sarah Waters is basically the queen of this niche. 'Fingersmith' is my top recommendation; it's a twisty, Dickensian romp with a great slow-burn dynamic between Maud and Sue. The class commentary is sharp, and the plot genuinely surprised me. Her other novel, 'Tipping the Velvet', is more of a picaresque journey through music halls and underground queer scenes—less polished plot-wise, maybe, but it's bursting with life and feels historically authentic in a grimy, delightful way.
Beyond Waters, I'd suggest 'The Paying Guests' (though it's post-WWI, so slightly later) for that intense, cooped-up-in-a-house dynamic. For something with a gentler, more atmospheric touch, Olivia Waite's 'The Lady's Guide to Celestial Mechanics' is Regency, not strictly Victorian, but captures a similar vibe of intellectual women finding love. If you're up for a mystery element, 'A Restless Truth' by Freya Marske is a fantasy-mystery on a transatlantic liner, but the central sapphic romance has that delicious historical tension. The Victorian setting just adds this layer of constant, thrilling risk that modern settings can't replicate.
And a quick side note: avoid anything that feels like a bland Regency romance with the pronouns swapped. The best ones use the historical constraints as a genuine source of conflict and character, not just wallpaper.