Assets
This module includes some premade maps and tokens and a vast collection of 3D Tiles, the assets included are continuously updated, you can get it HERE
By using the 3D Portraits Module, you can import your purchased 3D Minis from Heroforge. Heroforge also offers a 15$ a month subscription service that lets you use all the PRO customization and includes 5 Minis Purchases per month.
You can find plenty of free terrains here: https://sketchfab.com/search?q=tag%3Aterrain&sort_by=-likeCount&type=models
This guy has alot of good stuff, needs conversion to gltf: https://quaternius.com/index.html Free miniatures (requires account, stuff is paid but it's only for the 3d print, the model is free): https://www.shapeways.com/shops/dmworkshop How to convert STLs: https://youtu.be/2UwQ5v1uQy0
Skyboxes by Zachery “skiingpenguins” Slocum: https://opengameart.org/content/skiingpenguins-skybox-pack
Model Converter: https://products.aspose.app/3d/conversion/fbx-to-gltf Model Editor: https://threejs.org/editor/
Sketchfab has tons of free 3d assets that you can download already in the correct format: https://sketchfab.com/