I don't even like Colossus, which, among his war paintings, doesn't make any sense. I'm also not a big fan of his so-called Black Paintings, especially his Saturn, which doesn't make much more sense than this Colossus. I do like his tapestry cartoons and some of his portraits. I especially like his portraits that feature dramatic reds. The only one of this type that I don't care for is his washed-out Duke of Wellington, which doesn't count for red anyway.
Portrait of Don Manuel Osorio de Manrique Zuniga, Metropolitan Museum of Art, New York
Love this gem of a portrait. The boy's face is ordinary, but nothing else is. The little drama of cats and bird is suspenseful, and the flamboyant costume of the boy is delicious, especially set against the fantastic light display. Gimme this for my wall!
Count Floridablana , Banco de Espana, Madrid
Here's another portrait in red costume, also against a dark, but dramatic setting. When your eye wanders away from the count, there are several more faces to be seen, including a clock face and Goya himself.
Mourning Portrait of the Duchess of Alba, The Black Duchess, The Hispanic Society of America, New York City
The red in the costumes ties these two paintings, one black and the one below, The White Duchess, together. These reds and others he uses, like in the portraits above, can't possibly be unintentional.
Portrait of the Duchess of Alba, The White Duchess, The Alba Collection, Madrid
Old Men Eating, Prado Museum, Madrid
Here's one of Goya's Black Paintings. They're mostly of these dreary and macabre figures. One exception is Asmodea, which features--significantly!--a figure in scarlet costume.
*All these pictures, except Colossus, are copied from Goya Artwork. Thanks for putting together such a nice page.