Since you mentioned them -- as hard as it may be to believe -- HeNe lasers are only just beginning to be phased out in the semi industry in the somewhat esoteric use case of precision position measurement using interferometry. The output wavelength of a HeNe lase is extremely stable--with a simple feedback loop on the cavity length (ie, temperature) a HeNe laser is essentially an atomic clock locked to the 473.612248 THz 5s2 → 3p HeNe line. Interferometers built around such systems can accurately measure sub-nanometer displacements and are able to achieve a lifetime absolute stability of better than 10ppb--comparable to a rubidium atomic clock! [2]
[1] https://www.linde-gas.com/en/images/Gasworld%20Excimer%20Las...
- "Excimer laser gas mixtures are a combination of rare gases (argon, krypton, xenon, or neon) and halogen gases (fluorine or chlorine). The mixture of gases determines the wavelength of DUV light produced. Argon+fluorine+neon (193nm) and Krypton+fluorine+neon (248nm) are the two most common mixtures used. In terms of volume; neon makes up approximately 96–97.5% of the mixture."
https://www.linde-gas.com/en/images/Gasworld%20Excimer%20Las...