Collection of X-ray spectra from the four sources ordered into two panels according to their spectral shape. Top: NuSTAR spectra (FPMA/FPMB data both included) of V404 Cyg during the outburst period of 2015 (preceding intense X-ray flaring period), Cyg X–3 in the hard state, GRS 1915+105 during the anomalous low-luminosity state of 2019–2020 (preceding a period of sporadic X-ray and radio flaring), and the RXTE/PCA spectrum of V4641 Sgr during the outburst period of 2002. Bottom: NuSTAR spectra of V404 Cyg during the outburst period of 2015 (in between intense X-ray flaring), RXTE/PCA spectrum of V4641 Sgr during the outburst period of 2003, and NuSTAR spectra of GRS 1915+105 from the anomalous low-luminosity state (after the intense X-ray and radio flaring period). Note the spectral similarity between sources. The spectra of GRS 1915+105 and V4641 Sgr are renormalized by the amount shown for illustrative purposes.