This chapter describes ModelLib, a web-based platform for collecting models from different domains (e.g., electrical, mechanical, or electromechanical) and levels of abstractions (e.g., system, circuit, or device level). Use cases for this tool are presented, which show how it can support the design process of complex heterogeneous AMS systems through better reuse of existing models for tasks like architecture exploration, system validation, and creation of more and more elaborated models of the system. The current state of the implemented ModelLib prototype is described and an outlook on its further development is given.