A model set built specifically for the Sweet Home 3D interior-planning app: 1,602 zip files covering furniture, stairs, railings, and kitchen and bathroom fixtures.
Unlike most "free download" libraries, these are released under the Free Art License or CC-BY, so modifying and redistributing them is explicitly permitted, not merely tolerated.
Good for hobbyist home planning in Sweet Home 3D itself, and usable elsewhere since the format isn't locked to that one app.
Format is OBJ + MTL (Wavefront), so any tool that reads standard Wavefront files can use them.
Over a thousand free 3D models for interior design, from furniture to full room layouts.