Design a Mega Dog and Cat Clipart Bundle with Watercolor Illustrations showcasing different breeds of cats and dogs. The illustrations should depict the back view of the animals sitting in a relaxed posture. The bundle should have a total of 600 images and should cater to pet lovers of all ages. The watercolor style should be vibrant, with a blend of colors and should be appealing to the eyes. Ensure that the illustrations are detailed, and each breed should be identifiable at a glance