Zimmer collaborated with a number of mathematicians to apply the ideas from the Zimmer Program to other areas of mathematics. His collaboration with Alexander Lubotzky applied some of these ideas to arithmetic results on fundamental groups of manifolds. In collaboration with François Labourie and Shahar Mozes, cocycle superrigidity ideas were applied to the basic problem of the existence of compact locally homogeneous spaces of certain types. His collaboration with Amos Nevo concerned actions with stationary measure and provided certain basic structure theorems for such actions of higher rank semisimple groups. Zimmer's earlier work provided a proof of a conjecture of Alain Connes on orbit equivalence of actions of semisimple groups, and introduced the basic notion of amenable group action.