The gazebo_models repository has been migrated to the Ignition Fuel website. You can find more SDF models there, not only from Open Robotics, but also from anyone else who wants to upload some.

We're always uploading new models to Fuel, but there are some older models which haven't made it into the site yet. For example, since you're interested in indoor objects, take a look at the ServiceSim project's models.

Besides that, I think you can find models scattered across other online repositories. For example, there are some indoor models here.