8.72.3 Can you answer these questions?

8.72.3.1 Reference of plot not resolved

https://tex.stackexchange.com/landing/r/digest?cta=question&id=663848

The label of the first plot (added by \addlegendimage) appears in default black after two compilations which indicates that the reference of the first plot is not being resolved. Here is the code: 
\... 
[tikz-pgf] [pgfplots] [cross-referencing] [labels]
 

asked by el_maxx https://tex.stackexchange.com/landing/r/digest?cta=user&id=244589 Score of 1

8.72.3.2 Create an alphabet package that works like greek letters

https://tex.stackexchange.com/landing/r/digest?cta=question&id=664105

Some friends and I have been using LaTeX for some years and, at College, we have created some new letters to use with math (it was kind of a joke because we were constantly saying there were few ... 
[macros] [typography] [package-writing] [letters] [alphabet]
 

asked by Adame https://tex.stackexchange.com/landing/r/digest?cta=user&id=264591 Score of 1

8.72.3.3 Alternatives to the default font for letters to be used in the list of symbols?

https://tex.stackexchange.com/landing/r/digest?cta=question&id=664268

I am writing the symbol list and I am having problems because different physical quantities use the same symbol and therefore I need a different font (possibly not in math mode, so not inclined letter ... 
[fonts] [formatting] [symbols]
 

asked by Giuseppe https://tex.stackexchange.com/landing/r/digest?cta=user&id=223757 Score of 1