All free to use assets from the community are in this github repository, and item icons are specifically this folder:
To download things from the repo, read this guide I wrote.
It’s not that complicated, but feel free to ask questions if you get lost. I recommend using the Gitzip download method, personally, as it’s reusable for anything in the Repo and doesn’t require you to download the whole thing. Though, downloading the entire Repo is not a bad idea either.