The crassulaceae is a huge family with almost exclusively leaf-succulent plants. They occur all over the world, but predominantly in the Northern Hemisphere. In different regions grow different genera:
Echeveria and Dudleya in the Americas
Sempervivum, Orostachys and Rosularia in Eurasia
Sedum on the other hand is wide spread.
The single flowers of most crassulaceae are not as showy as cactus flowers. But the group-effect can be outstanding. As many crassulaceae have nice leaf-rosettes, they make a good subject for succulent growers.