This site lets you create normal maps based on images or a height map NormalMap-Online
Normal Map Online
Category: Textures
Poly Haven (Textures, HDRI’s & Models)
Here are two sites with CC0 (public domain) licensed images, one with textures (including bump, normal, roughness, etc) and one with High Dynamic Range Images (HDRI) which you can use to light your scenes. PolyHaven (F.K.A. HDRI Haven & Texture Haven) which also have Models for download