Six selected color-color diagrams showing the WISE-2MASS selection criteria to identify YSOs with infrared-excess. The gray dots in the background are all sources toward Orion B that pass the Gaia quality criteria plus the additional individual WISE and/or 2MASS selection conditions, as given in Appendix A.3 in the subpoints a to f. The black lines indicate the selection-borders and the black dots are selected YSO candidates toward the whole Orion B region as displayed in Fig. A.3. The blue dots are known YSO candidates (Megeath et al. 2012, 2016) and the magenta dots are the new YSO candidates that fall within the three subregions (see Fig. A.3). The numbers of selected YSO candidates are given in the respective color in the upper left corners (see also the legend on the right). The black arrows show the extinction vectors, with the individual length given in the lower right corners in A_V (mag).