Thanks for the advice! Yeah, I think I'll go ahead and leave a few free packs, but price the other ones.
Social media is your friend when you have a product. Whenever I make a new asset pack, I post it on Instagram, Reddit, Twitter(I'm bad at keeping up with Twitter tho haha), and Game Development Discord groups. I have an ex whose parents run a small business, their advice is to learn how to promote yourself whenever possible(Though be professional. Don't spam ads, people will ignore you.)
Also, engage with other creators. This means being active on social media and play other creators' games. There's a lot of really cool games available for free on itch.io that are typically made by small teams or individuals. Show them so love for their projects and they'll often return the favor.
Last thing, and I hesitate to say this since it looks like you're already pretty good at this, but make sure your packs are unique. You can find 93 individual slime asset packs on itch.io, but only one Beholder pack(which is honestly kind of weird since Dungeons and Dragons is so mainstream right now). Make stuff that no one else is making, and you'll drive up the demand for your art.
If you want to chat, feel free to reach out to me on instagram or twitter, my account is just Pop Shop Packs on either