I totally forgot about Afterlife but I'm glad that worked for you not once but twice. Congratulations!
Sometimes I look at the color of the dragon itself when I have to go outside the box and pick a dragon that has colors that are strong versus that color. In the case of Guardian, the color is purple so I figure since pink and green are enemies of purple maybe that dragon has a chance like Afterlife, Breeze, Sultana, Tulip or Summer Lily, etc.