—Megamodels are often used in MDE to describe collections of models and relationships between them. Typical collection-based operations – map, reduce, filter – cannot be applied directly to megamodels since these operators need to take relationships between models into consideration. In this paper, we propose adapted versions of these operators, demonstrating them on four megamodeling scenarios. We then analyze their applicability for handling industrial-sized megamodels. Finally, we report on a reference implementation of the operators and experimental results using it.