Distribution of the 3846 Galactic PNe in the HASH database (small grey dots). Overlaid are the 20 compact PNe (red dots) that form the spectral atlas presented in this paper, and also STRIPE83-0130 (a transient included for completeness). We also show 86 blindly selected Gaia sources (orange dots; Sect. 4.3) that have similar Gaia spectra as the compact PNe. Only 0.13% of Galactic PNe in HASH have measured sub-arcsecond diameters, and only one of these (DdDm-1) is located considerably outside the Galactic plane. The black line indicates the celestial equator. The shaded areas show the Euclid Wide Survey area that avoids the ecliptic and Galactic planes (for details see ESc22).