A vibration-damping system for turbomachine blade(s) in a turbomachine is provided. Each turbomachine blade includes a platform having a radially inner surface. The system includes a spacer axially adjacent the platform of at least one turbomachine blade in the turbomachine, e.g., adjacent a turbomachine blade stage. The spacer includes a body. A damping element coupler is on the body of the spacer, and a vibration-damping element is configured to couple to the damping element coupler. The vibration-damping element and the damping element coupler are disposed to cause the vibration-damping element to engage the radially inner surface of the platform of the turbomachine blade(s) to dampen vibration of the turbomachine blade(s), e.g., during operation of the turbomachine.