One thing that I noticed was the angles that the shots were taken at are the same. For instance, if one of the views of the toy truck was shot directly on at ground level that might have been enough of a difference. Same goes for the others. All shot at same angle. Great shots, focused, good exposure, great color.
I understand the birds, but the trucks seem like they should be accepted.
(Similar Content Versus Spam)
“Photographs: … Sending images with minimal differences, such as a slight change of angle, should be avoided. … Avoid using the following methods to add variation… . [LIST omitted; to see LIST, click link above].
(Similar Files Already Submitted; so, Similar Images Include ALL Images in Adobe Stock's Catalog) ... quality is better than quantity ... choose images that offer something UNIQUE to the buyer ... .
Note: The Adobe Stock curator could have cited the following issue but they are only required to cite one reason for rejection.
(Known Image Restrictions) > Scroll down to “Design IP” or search “toy” or “figurine”
The linked article above states clearly that it discusses SOME not all types of restrictions, but clearly the toy is owned by some entity that could sue over the photograph being publshed without permission.