Hi LaDonna,
I don’t know of any sources off the top of my head, but here are some places to try:
1. Look for clip art sources that allow you to reuse them for commercial purposes. Many of these sites are pay sites, but I do know free ones exist.
2. You can look for pictures that are considered part of the ‘public domain’. Those you can use without any problems.
3. Search Etsy for ‘digital collage’ sheets. You will have to pay to get the file, but I find there are lots of great sheets out there for under $5.
Good luck!