look at all the art and cultural detritus you love, or whatever most compells you (even if you dislike it, maybe especially so!). see if there are poses, objects, creatures, ideas etc that keep popping up. these are your prompts!!
𓅽 to use my own expierence as an example:
i kept finding human-bird hybrids everywhere in the stuff i return to. angels, harpies, Sirin & Alkonost, etc clearly something about the union of beast/bird with (often femme) humanity to create something either deceptive and dangerous or divine and distant made me excited! so that became my prompt. it made me start having questions i could only answer through making art: how many ways can i depict a human-bird hybrid? what details transform it from an angel into a siren, or perhaps into something all together new and different? etc
this leads me to:
𓅽 explore mythology, fairy and folktales! i personally don't buy into the jungian shit AT ALL (and don't even get me started on joseph campell, booo) but! there's a reason these stories and their imagery have stuck around! they're endlessly fascinating and adaptable, and they make for a great first step to take in creating something that speaks to you and so many others across time and space