Which three succulent plants are referred to as the "Three Immortals" of succulents?
What are the "Three Immortals" among succulent plants?

The "Three Immortals" of succulents are Echeveria 'Guanghan Gong', Echeveria 'Afterglow' and Echeveria 'Blue Light'. Echeveria 'Guanghan Gong' is a large rosette-shaped Echeveria with good heat and cold tolerance; in winter its plant becomes fuller and more compact. Echeveria 'Afterglow' has a white powdery coating on its leaves, which grow fairly tightly packed, and its color is generally a lighter blue-pink or purple-pink. Echeveria 'Blue Light' has relatively thin leaves, with red tips and edges, while the leaf blades are generally pinkish blue.