Materials + texture data for the rocks in the Variant Rock Gallery since they're kind of broken in Creative.
From my testing the project size can range from 5-10% depending on how many rocks you are using. However something VERY IMPORTANT is that I did NOT optimize any textures, they're all rendered at LOD Bias 0, so if you're struggling with project size don't worry, you can significantly reduce the download size by sacrificing some texture quality.
!!! It's best practice to add the folder to your project while it is NOT open, this seems to avoid random validation issues, then when you do open the project I recommend right clicking on the "ApolloRockMaster" folder and then selecting "Resave all" !!!
Replace each rock's texture data with the corresponding one included in the download, this is easy if you just use the name of the texture data already in place as reference (I've named all the texture data assets included in the zip the same way they're named in UEFN).
Below is a video of me setting up every rock.
Click on the text above to download, if that doesn't work:
https://drive.google.com/file/d/1dHh2MXW3_WUFf8cjDs0_KlFgdsz9kQsa/view?usp=sharing