Top panel: upper limits on average isotropic–equivalent luminosities of potential γ-ray counterparts to FRBs as a function of integration time (red upside down triangles). For comparison, L-GRBs (blue squares) and S-GRBs (grey circles) are also shown (from Tsvetkova et al. 2017), along with the sub-luminous short GRB 170817A associated with GW 170817 (purple pentagon) and the giant flare of Galactic magnetar SGR 1806-20 (orange diamond). Low-luminosity GRBs populate the shaded area, with prototypical GRB 980425 explicitly shown (light blue square). Uncertainties on luminosities have comparable sizes with symbols. Bottom panel: same as the top panel, with isotropic-equivalent radiated energy E_γ, iso instead of isotropic-equivalent luminosity. The GRB timescales here correspond to T₉₀ durations.