Totally depends on your requirement. Please also provide more information as
even within the one discipline of chemistry the field of standards is very wide
indeed. Otherwise check the following source for the general starting point of
selection of analytical reference standards.
https://www.symteraanalytics.com/Blog/Choose-Proper-Analytical-Reference-Standards
I know that it depends on specific scenarios or requirements. Currently, I was
looking for initial guidelines. So thank you for sharing this source. In case
of further help, I will get back to you with one discipline for my case.