The Millionaires are a family who appear in House of Bloo's. The family members are: the wealthy rich man with gentleman's character, his wife with smile on her face, and their perfectly spoiled daughter with changed character. They also make cameos in certain episodes.
In House of Bloo's, the Millionaires stopped by Foster's to find an imaginary friend for their spoiled daughter. The family explicitly states that they only want the best for their daughter, and so Frankie and Mr. Herriman introduced Duchess to them. The couple agreed and went to Mr. Herriman's office to sign the adoption papers. Meanwhile, their daughter spots Bloo and immediately becomes dead set on taking him home, and even insisted on naming him "Tiffany." Eduardo quickly snatches Bloo, and she immediately starts chasing after him.
Eduardo, Wilt and Coco spent all day trying to keep Bloo out of reach if the little girl and prevent him from being adopted before Mac comes back to visit Foster's. The Millionaires' daughter, however, finally ends up getting him and went downstairs to tell her parents that she wanted Bloo instead of Duchess. Before they could agree to adopt Bloo, however, Mac shows up and explains that he was at school. Frankie still tried to get them to adopt Duchess, but the daughter rudely refused and stormed out. The family then leaves, with the couple deciding to get their daughter another pony instead.
Mr. and Mrs. Millionaires make a background cameos in The Buck Swaps Here. Their daughter, however, does not.