They’re open for a special dark fantasy and psychological thriller flash fiction call, for “prose that is troubling, that explores our darkest fears. We're not quite sure we're ready for this to be honest, but that's part of the appeal. We are looking for literary prose. We do not want to weather gratuitous violence or cruelty, but we do--or at least we think we do--want to feel fright, unease, a racing heart. If you are a writer of stories that do this, this call is for you. Think Shirley Jackson. Our usual guidelines apply. … Please indicate that your submission is for the Dark Fantasy and Psychological thriller submissions call.” 
Apart from this call, they’re also open for unthemed flash narratives – fiction, non-fiction, and hybrid (between fiction and non-fiction). They also accept reviews of flash collections, essays on craft, and articles on teaching flash for their blog; these are unpaid. Submissions are fee-free until 30th June; after that, there will be a charge for submissions through the rest of the reading period.
Deadline: 30 June 2025 for fee-free submissions
Length: Up to 1,000 words
Pay: $300 for dark fantasy and psychological thriller fiction; $100 for general submissions ($150 with audio)
Details here and here (they have various categories in Submittable, please be sure to submit in the correct one)

Deadline: June 30th, 2025