One of my favorite and most long-standing texture resource websites. I prefer simple, straight image files where I don't need to juggle with .sbsar files.
Poliigon is a long-standing staple in the 3D asset community. I trust their quality standards and have personally used their assets in many different productions.
I've used these so much in various productions! "Indoor Scapes", "Jungle Scapes", "Creeper Scapes". Each comes with a usefully categorized collection of vegetation for dressing different biomes.
Quickly add optimized animated 3D dust particle animations to your scene. To be fair, with it's interface, this is just as much an addon as it is an asset.