Altermagnets are discussed as a distinct class of compensated magnets where time reversal is only undone by real-space rotations (or mirror symmetries), resulting in broken Kramers degeneracy. Most proposal rely on low symmetry crystal structures for realising the requirements but we show that correlation driven instabilities can lead to the spontaneous formation of altermagnetic phases. We discuss various example of interaction induced collinear even and odd wave magnets and how two detect these in experiments.