If you want a more minimalist or patterned look, Dreamstime provides seamless cloud patterns perfect for desktops.
For a softer, more calming vibe, these pastel-colored backgrounds are excellent: 1920x1080 Cute and Puffy Cartoon Clouds Hoverin...
For a bit of personality, Freepik features "smiling" cloud illustrations that add a friendly touch to your screen. Pastel & Aesthetic Clouds If you want a more minimalist or patterned
For a traditional look, Shutterstock offers a variety of "hovering" cloud styles with soft blue backgrounds. more calming vibe
These options feature a clean, vibrant aesthetic typical of modern animation:
Vecteezy has "fairy-tale" themed backgrounds that include subtle star elements and gradient skies. Visual Inspiration Grid
Sites like Wallpapers.com feature artistic, watercolor-style clouds in pink, purple, and blue hues.