The Magellanic Clouds are exceptional galaxies for the study of massive stars and other luminous objects, because they are close and seen in directions where the galactic interstellar extinction is relatively low. In addition the Small Magellanic Cloud (SMC) is of special interest because of the possible peculiar effects that its low metal abundance, compared to the Solar neighbourhood, may have on the evolution of its stellar population. Consequently, a search for the most luminous SMC members has been the subject of many studies. Among the different means used to detect SMC members, the wide field cameras equipped with objective prisms, Grisms or Grenses have played a prominent part. The method consists of selecting stellar objects showing high luminosity or typical spectral features. Such surveys have been especially successful in detecting SMC Ha emission-line objects (Henize, 1956; Lindsay, 1961), OB and blue supergiant stars (Sanduleak, 1968, 1969), planetary nebulae (Sanduleak et al., 1978; Sanduleak and Pesch, 1981) or carbon and late M-type stars (Blanco et al., 1980).