Electric Spec is an established online magazine looking to publish speculative fiction and art:
Electric Spec is a not-for-profit speculative fiction magazine published four times per year. Our primary goal is getting great speculative fiction into the hands (or screens) of readers. Since 2005, we've been publishing short stories from authors all over the world. We've worked with all kinds of authors, from published professionals to new writers. We also believe in the value of the editorial process, and we edit every story we publish.
The editors want fiction between 250 and 7,000 words, paying $20 USD per piece. They’re always open to submissions and publish quarterly.
Literarium listing is here: https://literarium.net/market/electric-spec/electric-spec/