The catalogue was compiled from suitable data available in literature and from the data measured or created by the project "18NRM02 PRISM-eBT" (Primary standards and traceable measurement methods for X-ray emitting electronic brachytherapy devices; http://www.ebt-empir.eu/) of the European Metrology Programme for Innovation and Research (EMPIR). The main goal of the catalogue was to develop a set of harmonised reference X-ray qualities denoted as “eBT equivalent” that would be established for in-laboratory activities by the X-ray tubes usually available for calibration in calibration laboratories, but the tube voltage and the filter are specifically selected to simulate the energy spectrum of the corresponding eBT radiation as closely as possible at the reference point. The catalogue contains the following spectra: 1) X-ray spectra for 35 kVp, 50 kVp and 70 kVp in air at 100 cm distance calculated with SpekCalc software. 2) eBT-equivalent spectra in air at 100 cm source-to-detector distance calculated from 2) with SpekPy software. 3) X-ray spectra for 35 kVp, 50 kVp and 70 kVp at device entrance window (0 cm air thickness) that were analytically recalculated from 1). 4) X-ray spectra for 35 kVp, 50 kVp and 70 kVp in 1 cm water depth obtained using Monte Carlo calculation from 3). 5) eBT-equivalent spectra at 1 cm water depth calculated from 4) with SpekPy software.