Create a set of watercolor clipart birthday motifs with a delightful and childlike essence. Use the medium of watercolor to infuse the images with vibrant colors and gentle textures. Draw inspiration from classic children's book illustrations, reminiscent of artists like Quentin Blake and Beatrix Potter. Depict cheerful birthday elements such as balloons, party hats, cakes, and presents, with a whimsical and playful touch.