I just read through the Witchlight article in the latest Dragon+ and I note at the bottom it states:I think a Feywild counterpart to Van Richten's seems not-unlikely to me. Hopefully they'll reprint the satyr race there, too, which feels like a weird omission from Witchlight.
“We’re also planning to create something similar to The Tortle Package, which we released on the DMs Guild to coincide with Tomb of Annihilation,” Chris reports. “This will be inspirational material that’s completely standalone and will explain how to create your own archfey and their Feywild domains. Once you’ve had a taste of what we’ve created in The Wild Beyond the Witchlight, you can go off and create your own.”
That makes me think that we'll get a PDF-only "Build Your Own Feywild Domain of Delight" mini-setting product, rather than a full-on hardcover.