It’s a good idea. A collection of small codes that uses Fortran features, including those from recent standards, is needed. Would GitHub - scivision/fortran2018-examples: Fortran 2018 standard examples with broad applications be a good starting point? @urbanjost has many codes to demonstrate intrinsic functions at GitHub - urbanjost/M_intrinsics: man-page style descriptions of Fortran intrinsics for use as a reference for developers and tutorials .
A related thread is Fortran Compiler Testing Framework .