Hidden formatting tricks

Is there a repository where all the common formatting “tricks” are listed?
For instance, I have already learned the following:
\hat{p} makes p-hat
\pm makes +/-

I only know these because I found them in other peoples codes. Is there a repository somewhere that has all the common codes. Currently I’m wanting to do nothing more fancy than make a subscript, but haven’t a clue how to do that. But there are other things I would do if I only knew they were possible.

They’re all LaTeX codes, so search for that. They’re not all supported by Desmos though.