I will present an overview of some of the deepest and widest narrow-band surveys ever undertaken with 2-8 m telescopes. These surveys have been able to select large, robust samples of H-alpha (Ha) star-forming galaxies from z~0 to z~2.5 (corresponding to look-back times up to ~11 Gyrs) in a uniform manner over ~1–10 deg2 areas in fields like COSMOS, UDS or SA22. Overall, the results reveal the exponential decline of the typical star-formation rate of galaxies (SFR*) over the last 11 billion years, and very little evolution in the stellar mass function of H-alpha selected star-forming galaxies, with strong implications to the main drivers of galaxy evolution. I will also highlight how the homogeneously selected samples of Ha emitters across cosmic time are ideal to unveil the evolution of the ionised gas dynamics, and to study dust properties, clustering, environment, and (resolved) metallicities of typical star-forming galaxies since the peak of the star formation history. Finally, I will show how JWST will open a new window for Ha blind surveys to z~6.