Prefabs

Prefabs allow for an object and all its components to be saved into a single asset.
These are especially useful for things like light fixtures or pickupables! Combine a light source and a 3D model into a prefab! Combine a pickupable, its vrc_pickup script and its collider(s) into a prefab!
Check out the Udon prefabs section[docs.google.com] of VRCPrefabs. I also recommend Vowgan’s Collision Sounds[vowgan.booth.pm], they are incredibly satisfying.
Day/Night Cycle
This is a fork (edit) I made of an Udon system originally made by Nova_Max. It has the ability to make the directional light (sun) rotate around the world, along with a moon, stars, and changing cubemaps depending on the time of day.