What characters did Disney lose the rights to?

Could you elaborate on the specific Disney characters that the company has lost the rights to in recent years? Are these characters from classic animated films or more recent franchises? How did Disney lose these rights, and what impact has it had on the company's intellectual property portfolio? Additionally, are there any notable examples of Disney regaining rights to characters in the past, and what strategies might the company employ in the future to retain ownership of its beloved characters?