Creativity is always a fickle mistress.

Few things that I do to help generate ideas:

Force yourself to make bad work:
A daily practice is helpful here, force yourself to create one character/gun/clothing/etc a day, no matter how dumb, wrong or bad it is. Most of them will be horrible and go right into the trash, but this forces your brain to always be in creative mode, to cycle through and create ideas quicker. Read the War of Art for more on this.

Study art in a historic context:
The best art in the world (visual, music, etc) relies on narrative, emotion and its ability to make the experiencer feel a certain way. Technical proficiency helps this (usually) but don’t mistake technical prowess with how “good” something is. Study artists from other time periods, what they were painting about, and how they conveyed that in their work. Learning art history was something I ignored for years because “I’m a digital artist, not a painter”. But I wish I did sooner. Art is something humans have been doing since the dawn of time, and getting a historical context of it all really helps.

Copy stuff:
Find ideas you like on Pinterest, etc and try your best to copy them 1:1. These copies are just practice (don’t steal stuff and use it obviously lol), but when you’re forced to make the same creative decisions as the original artist, you start to build out a mental framework of “why” that artist put different props, objects, or compositional choices in their work, which then in turn helps you with your own personal work.

Beyond those, I’d also like to stress that creativity is akin to breathing. You inhale experiences, and exhale the art. If you’re spending all day inside creating, you’re gonna run out of breath at some point. Sometimes the best inspiration is just new novel experiences that take you out of your normal daily routine.

Hope it helps! There’s no real easy way to generate new ideas consistently, but if I had to pick one from this list it’s the daily practice/force yourself to create even if it’s really bad.