Hertzsprung-Russell diagram based on Gaia data of all 321 β Cep stars from the literature (circles) and the 121 new stars in our Gaia-informed sample (squares, new detections). The typical uncertainty is indicated in the lower left. The black outlines show the instability regions for p-modes (solid, β Cep, l = 0−2), and g-modes (dashed, SPB, l = 1−2) based on the calculations from Burssens et al. (2020). The main sequence evolutionary tracks of Burssens et al. (2020) are shown in grey. The colour-coding gives the main pulsation frequency of the stars cut off at 12 d⁻¹. Stars marked with a red cross do not exhibit β Cep variability in TESS. The top axis marks the spectral type.