Lots of short fiction publications stick to specific styles or genres of fiction. But there are also some which focus, either typically or occasionally, on prompts or particular themes. Writing for these can be great, especially if you've been feeling stuck recently. But there can be some things you might want to consider before you begin a story geared for one of those markets.
First, let's start with the up-side. Writing from a prompt can help you sort of "jump start" the creative process. Here, sometimes a really specific prompt can be helpful, as it forces you to focus on one idea and brainstorm around it. A prompt or a theme of "animals" may not do a whole lot to help you come up with a new idea but one on "a vacation gone awry" -- well, there you can start thinking "OK, what kind of vacation?" and "How does it go awry?" and all sorts of things like that. It gives you a little something to latch onto and work from. These prompts also often have a deadline, which can be a great motivator.
Also, from a purely pragmatic side, my impression has been that in quite a few cases your "odds" are somewhat better for publication. If a themed issue or anthology is trying to fill X slots and they get 10X submissions then you're at least potentially better off than sending the same story to an unthemed publication which is trying to fill X slots and gets 20X or 50X submissions. Obviously, this won't help you if your story is poor or just doesn't strike the editor's fancy. But if you're regularly getting into that place where you're "in the final cut", etc. then you might make a few dollars on this type of sale.
And that leads into the first downside... You probably will only make a few dollars. There are few themed/prompted publications out there which pay professional rates for short fiction. More often, you're looking at a semi-pro rate of a penny or two a word or a smallish flat rate. And, since there's a deadline involved, you won't usually have time to send the story to higher-paying markets first.
Which leads to another point... Remember those specific prompts that helped jump start your writing? Well, if the prompt is too specific, guess what? It might be a hard sell to another publication. This is for a couple of reasons. One -- they may very well see quite a few stories submitted all at once around the same theme. ("Gee, Ethel, I wonder why we're getting all these vacation in space gone bad stories this week?") Two -- if the theme is too distinctive then it may be obvious that your story was written for (and rejected by) that particular market. On the one hand, I would think that wouldn't matter so much -- if it's a good story, it's a good story, right? On the other hand, at least one publication explicitly says that it's a hard sell to send them "stories originally intended for someone's upcoming theme anthology or issue" so it's worth keeping that in mind.
Writing for a prompt or themed issue of a publication can be a lot of fun and a good way to keep yourself moving forward with new writing. If you want to look at a big list of upcoming themed/prompted deadlines, Duotrope has a list of those which you can search. Just remember that there are some possible trade-offs when writing these stories and plan your time accordingly.