If you're looking for anime similar to Little Nemo: Adventures in Slumberland Pilot (1984), you might like these titles.
Follows the dream of a young boy in which a happy cat named Pero and a strange whale appear.
Dreams drive us to create a better future! One day in the Sunshine Forest, Doby and Disy find out that their friends did not wake up after falling asleep. So, they decide to get into their friends’ dreams to save them and there, they meet the Daydream Fairy.
A middle school girl named Yume sees something fall from the sky, and meets a pale violet-colored kitten named Mew. It turns out that Mew has the power of "Yume Synchro" (Dream Synchro), the power to enter dreams. In the dream world, the girl and Mew collect Dream Stones.
Three friends face many challenges on their adventure to Rainbow Mountain, a magical place where the first rainbow is said to have been created.