The most common cell-based assays can be categorized into signaling, viability, proliferation, cell death, and cytotoxicity assays. Signaling assays are designed to detect cell response to external stimuli, while viability assays assess the durability and health of cells under various conditions. Proliferation assays measure the growth rate of cells, cell death assays measure the mechanism and rate of cell death, and cytotoxicity assays measure the effect of substances on cells.