The latest NAMD 3.0 releases provide GPU-resident molecular dynamics simulation support for external forces, now including Colvars and Tcl Forces. This support allows users to take advantage of a great variety of additional forces in their GPU-accelerated simulations and free energy calculations. The Colvars (collective variables) module and Tcl Forces scripting both provide mechanisms to define external forces between groups of atoms, allowing control over specific structural features during a simulation to enable the study of complex biomolecular processes and interactions. These valuable capabilities are now available from within NAMD's fastest simulation mode.