Didn't you already create a thread the other day about this? Regardless here's some things that come to mind.
I think your best asking in forums and websites where artists are looking for content. I would also advise you take the initiative to see the common things people are asking already, what problems they have, what things they cant find online etc. There is lots of content that can be created to automate or make things easier for artists. That's why these assets are for sale, people wouldn't buy them if they didn't bring them value or time saved.
The issue with this thread is that you are asking people who have worked hard and built their business/side hustle by either experimentation, trial/error, or simply lots of research. Imagine if you had a successful bakery and someone builds a bakery across the road, comes into your business and asks you whats your best selling product? You probably wouldn't want to share that information otherwise their bakery might start taking your customers. We are all here to help each other but keep in mind you need to do the leg work and what works for someone else might not work for you so I highly suggest you just start creating, do things you are good at or enjoy doing. You haven't uploaded 1 model yet so get to it.
