TOI-178 planets compared to other known transiting exoplanets with radius and mass uncertainties less than 40% (grey) and other systems known to harbour a Laplace resonance. Data on known exoplanets were taken from the NASA Exoplanet Archive on 18 September 2020. The dashed lines show theoretical mass-radius curves for some idealised compositions (Zeng et al. 2019). The six planets orbiting around TOI-178 are indicated; the colour of the points and error bars give the equilibrium temperature. The seven planets orbiting Trappist-1 are shown with diamonds, and the parameters are taken from Agol et al. (2021). The three planets orbiting Kepler-60 are shown with ‘X’ marks, and the parameters are taken from Jontof-Hutter et al. (2016). The six planets orbiting K2-138 are shown with squares, and the parameters are taken from Lopez et al. (2019). The four planets orbiting Kepler-80 are shown with inverse triangles, and the parameters are taken from MacDonald et al. (2016). The four planets orbiting Kepler-223 are shown with regular triangles, and the parameters are taken from Mills et al. (2016).