On Blenderkit you can find models, materials, HDRs, scenes and brushes you can use directly in Blender. Some are free, many are part of a subscription based Full Plan.
Blenderkit
Category: 3D Models
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