In this thesis I discuss different options to extend the number of degrees of freedom for wave control in metamaterials. The first part explores how additional compacted dimensions might be realised by engineering geometrical singularities in structured plasmonic surfaces, focusing on graphene implementations. A semiclassical treatment of nonlocality in singular plasmonic metasurfaces is provided, along with more accurate models of the effects of common graphene substrates. The second part deals with the use of the dimension of time as an additional degree of freedom for metamaterials. I propose a new strategy based on temporal inhomogeneities for coupling far-field radiation with evanescent modes, realising the temporal analogue of the Wood anomaly in plasmonics, and then continue with two new instances of nonreciprocal wave effects, demonstrating how Fresnel drag can be engineered in spatiotemporally modulated matter at rest. Finally, I show a novel amplification mechanism, based on copropagating travelling-wave modulations, and propose a class of implementations in double-layer, dispersive conductive surfaces.