Uncharted Magazine is now open to SFF and Horror short stories of between 1,000-5,000 words. Payment is a flat $200. You can find more information here.
Fairytale Review is open until July 6, 2021 for a themed issue on sleep. They are looking for flash fiction of no more than 1,000 words, and payment is a flat $50. You can find full information about the theme and submitting here.
Silver Shamrock Publishing is holding an open call for their horror anthology Midnight Beyond The Stars. Payment is 6 cents per word for stories of between 2,500 and 6,000 words. Full details can be found here.