The BBC posted an online archive of many of its sound effects. The nature scenes and peculiar things of historical interests are wonderful, though the broad focus seems to be components for radio plays and the like: footsteps, actions, incidental moments.
The BBC license isn't free and has odd stipulations, but the point of the project and its accompanying rules is remarkable: "RemArc, or Reminiscence Archive, is designed to help trigger memories in people with dementia using BBC Archive material as stimulation. "
