Cosmic World: floating planets, rings around giant moons, cosmic waterfalls, galaxies beneath the horizon
Moonlit World: giant moon, silver clouds, dark blue sky, glowing lakes, mysterious ancient ruins
Sky World: floating islands, waterfalls falling into clouds, enormous celestial temples, endless sunset sky
I’d use combinations like “floating islands + giant moon + glowing lake + aurora + fantasy ruins + cosmic sky” rather than trying to make the scene completely realistic.