External Assets

Multi Ressources Sites

• Open Game Art • 3D/2D/Sounds and Music/Concept Art and more
• Reiner's Tilesets • Great collection of 3D models all textured, 2d graphics, applications and some textures
• Sitter's Electronics • 29 Packs of 3D models, all textured, + some extras (textures,skyboxes,sounds)
• Free the models • Great collection of 3D models + extras (textures, animated textures)
• HasGraphics • 2D graphics site reference (sprites, tilesets, tools)
• Psionic Games • 3D models, Sound effects, Textures
• Nobiax's Models • Great 3D Models packs, all textured

Textures

• Nobiax's Textures • Many Packs of textures, including diffuse, specular, normals
• SpiralGraphics • Generated Textures
• TextureLib • Photography Textures
• Mayang • Photography Textures
• GfxPlace • Various Game Graphics

Sounds & Music

• FreeSfx
• Incompetech
• Soughafter Sounds
• Partners in Ryhme
• Matthew Pablo

Ressources in .blend format

• Blender Swap
• Kator Legaz • 3D Models, Mostly interior/exterior stuff
• Blogscopia • 3D models, Mostly interior/exterior stuff
• Blender open material repository

About licenses : Most of the sites listed here offer contents that is usable commercially, just make sure to check again the item's license and terms before using it.