Could anyone provide a list (even if it is incomplete) or a link to find which variables from observations does ERA5 assimilate?

I have been going through the documentation and found some hints but I cannot find a clear and complete list of variables. I understand that the assimilation of data depends on the availability of that data, but I would like to know which variables are assimilated if available.

Documentation that I have looked into:

Hersbach, H, et al (2019) Global reanalysis: goodbye ERA-Interim, hello ERA5. ECMWF Newsletter 159, 17-24. http://dx.doi.org/10.21957/vf291hehd7

Hersbach, H., et al (2018) Operational global reanalysis: progress, future directions and synergies with NWP, ECMWF. ERA Report Series 27. http://dx.doi.org/10.21957/tkic6g3wm

IFS DOCUMENTATION – Cy41r2