We provide line luminosities and spectroscopic templates of prominent optical emission lines of 133 Galactic Wolf-Rayet stars by exploiting Gaia DR3 parallaxes and optical spectrophotometry, and provide comparisons with 112 counterparts in the Magellanic Clouds. Average line luminosities of the broad blue (He 𝜆4686, C 𝜆𝜆4647,51, N 𝜆𝜆4634,41, N 𝜆𝜆4603,20) and yellow (C 𝜆𝜆5801,12) emission features for WN, WN/C, WC and WO stars have application in characterising the Wolf-Rayet populations of star-forming regions of distant, unresolved galaxies. Early-type WN stars reveal lower line luminosities in more metal poor environments, but the situation is less clear for late-type WN stars. LMC WC4-5 line luminosities are higher than their Milky Way counterparts, with line luminosities of Magellanic Cloud WO stars higher than Galactic stars. We highlight other prominent optical emission lines, N 𝜆𝜆3478,85 for WN and WN/C stars, O 𝜆𝜆3403,13 for WC and WO stars and O 𝜆𝜆3811,34 for WO stars. We apply our calibrations to representative metal-poor and metal-rich WR galaxies, IC 4870 and NGC 3049, respectively, with spectral templates also applied based on a realistic mix of subtypes. Finally, the global blue and C 𝜆𝜆5801,12 line luminosities of the Large (Small) Magellanic Clouds are 2.6×10 38 erg s −1 (9×10 36 erg s −1 ) and 8.8×10 37 erg s −1 (4×10 36 erg s −1 ), respectively, with the cumulative WR line luminosity of the Milky Way estimated to be an order of magnitude higher than the LMC.