The European Spallation Source aspires to become the world's leading neutron source for the studies of materials during the next decade. At ESS 16 different instruments will be built. These instruments will require neutron beam monitors with high precision, low gamma sensitivity, high time and space resolution. Such neutron beam monitors are essential in various neutron experiments to continuously diagnose the delivered beam. In this work different types of neutron beam monitors from different suppliers have been characterized using the R2D2 beamline at IFE in Norway and using a Be-based neutron source. For the gamma sensitivity measurements different gamma sources have been used. The evaluation of these monitors includes the study of their efficiency, attenuation, uniformity, stability, and their sensitivity to gamma. In this work we report the results of this characterization.