Light curves of three sources in our sample illustrating the types of variability defined in this work (see Sect. 4.1.1). Circles represent the ZTF g band (green) and r band (red), while grey diamonds correspond to the NEOWISE W2 band. For clarity, the g-band and the W2-band light curves are vertically offset in all three panels, and the SR example is binned to better show its long-term evolution. The reference modified Julian date (MJD) corresponds to the start of the ZTF survey.