Elliot Handler, who co-founded the Mattel toy company and designed the plastic playthings that have filled millions of Christmas stockings, made dinner parties possible by occupying otherwise fidgety children, and stubbed countless parents’ toes, died on Thursday at his home in Los Angeles. He was 95. The cause was heart failure, his daughter, Barbara Segal, said. Mr. Handler helped introduce Barbie, helped design the talking doll Chatty Cathy and popularized Hot Wheels toy cars. He began Mattel in 1945 with his wife, Ruth, and a short-term partner. Until the Handlers were forced out of Mattel in 1975, they oversaw a...