Pro Se Press has a long list of open calls for their novella anthologies. These are pulp fiction and of various genres some set in worlds they've created and for which you need to request their bible. Stories word counts run from 8000 to 12,500 words depending on the call. Writers have to query first, so you won't be writing something that you'll have to be hunting down another market for. You can find the details and various calls here.
Their submission page with even more details can be found here. On this page you'll find the dates for reading periods for collections, digests, and novel submissions. They also publish a quarterly magazine for shorts of 3000 to 30,000 words.
There are no pay specifics listed for any of their projects so that is something you'll need to query about or they will inform you if your query has been accepted.