The materials Roblox give you is good I’m sure if you search ‘texture pack’ in the toolbox you’ll find some useful textures and see whatever suits your liking but you’ll be better off finding other textures to make your builds more immersive - realistic In a kind of way.
If your looking just for known specific textures that are normally used for flooring, houses, wall interior, ect. There’s a few textures sites that could achieve that realistic approach.
The dev forum has resources - tutorials for either making your own or using free texture here is something you could take a look at: Free texture sites