Model transformations are essential elements of Model-driven Engineering (MDE) solutions, as they enable the automatic manipulation of models. MDE promotes the creation of domain-specific metamodels, but without proper reuse mechanisms, model transformations need to be developed from scratch for each new metamodel. In this paper, our goal is to understand whether transformation reuse across metamodels is needed by the community, evaluate its current state, identify practical needs and propose promising lines for further research. For this purpose, we first report on a survey to understand the reuse approaches used currently in practice and the needs of the community. Then, we propose a classification of reuse techniques based on a feature model, and compare a sample of specific approaches – model types, concepts, a-posteriori typing, multilevel modeling, typing requirement models, facet-oriented modeling, mapping operators, constraint-based model types, and design patterns for model transformations – based on this feature model and a common example. We discuss strengths and weaknesses of each approach, provide a reading grid used to compare their features, compare with community needs, identify gaps in current transformation reuse approaches in relation to these needs and propose future research directions.