- People pictures - clothing catalogs
- Food pictures - grocery ads (for basics) or food magazines (for prepared dishes)
- Plant/flower pictures - seed catalogs
- And so forth.
My recent discovery: use realtor magazines/listings (those free magazines at the entrance of the grocery store) for pictures of houses. You could make house collages by gluing house pictures onto paper. Or mount the houses on note cards and attach to cups or blocks - to build neighborhoods in the blocks center.