This dataset contains all emission-line lists and PyEMILI output files used in the analysis presented in “PyEMILI: A New-Generation Computer-Aided Spectral Line Identifier. II. Emission-Line Identification and Plasma Diagnostics of a Sample of Gaseous Nebulae” (arXiv:2511.14451). A total of 34 samples were analyzed.For each sample, two files are provided (each named after the object): 1. Summary line identification list (*.dat) Each .dat file contains the observed emission lines used as input for PyEMILI. These files are described in the corresponding article in the Appendix Table A.1. File format Column 1: Observed wavelength after velocity correction Column 2: Observed line flux normalized to I(Hβ)=1 Right of the ‘|’: Best candidate identification(s), including the corresponding wavelengths and ion symbols. Asterisks * mark lines where the literature ID does not match PyEMILI’s best candidate Question marks ? mark lines that were not identified in the literature 2. Complete line identification list (*.out) Each .out file contains the full identification results for every line in the corresponding .dat file. These files are described in the corresponding article in the Appendix Table B.1. These files include: All candidate ID(s) for each line The information on candidate wavelengths, ions, and multiplets, etc. More descriptions are here