This chapter presents an overview on the state of art of the controlled assembly of plasmonic nanoparticles (NP) clusters by colloid chemistry methods, while describing their plasmonic properties and applications, with a special emphasis in sensing through surface-enhanced Raman scattering (SERS) spectroscopy for biodetection purposes. It deals with experimental preparation approaches, starting with a quick snapshot of the wide diversity of anisotropic plasmonic building blocks currently available. The chapter describes the existing approaches for controlled assembly (focusing on discrete clusters). It discusses the broad range of possibilities to be explored with hetero-clusters, following with an overview of the existing separation methods, since this is an important step to obtain colloidal discrete NP clusters in high yield. The chapter describes the plasmonic properties that the discrete clusters possess, arising from their close gaps (LSPR coupling), and the emerging applications for these materials, stressing SERS-based biodetection.