Late-time NIR spectra of SN 2018ibb and the slow-evolving SLSNe LSQ14an and SN 2015bn. The strongest features are labelled. SN 2018ibb is the only SLSN that shows cobalt in emission, which has its strongest optical-NIR feature at 1.025 μm. Its luminosity translates to a nickel mass of ≳30 M_⊙, consistent with the light curve modelling. All spectra are scaled so that O Iλ 7773 has the same amplitude in all objects. Regions of strong atmospheric absorption are cropped.