Many different colorful succulents make excellent garden-partners, such as campfire Crassulas (Crassula capitella "campfire") and hybrids from the genus Echeveria. These two plants work well together because they have different structures – Echeveria are frilly and dainty, while Crassulas are bold and strong looking. Additionally, Crassulas often change color depending on the amount of sunlight striking them, which provides variation in your succulent garden.
Most succulent species are quite hardy, which is a large part of their appeal. Most types work well together because they are such undemanding plants. Other examples of colorful succulents that you can mix and match include other Crassulas, such as shark’s tooth (Crassula corymbulosa), tree aeonium (Aeonium arboreum) and paddle plants (Kalanchoe thyrsiflora). Be careful that you don't expose your plants to temperatures below which they can remain viable.
The definition of the term “succulent” varies slightly between botanists and gardeners. Gardeners usually exclude cacti from succulents, whereas botanists define succulents as plants that store water in their tissues and therefore include cacti in the succulent group. It's important to understand that the term succulent is descriptive and doesn't refer to any distinct lineage of plant. Succulent species occur in many different families and genera.