*.gnucash (or the like) will work in any normal shell (zsh, bash, tcsh, ksh, sh etc.)
If this is not working, then either you're using some shell that is not behaving in an expected way (not sure if globbing like this is a posix standard or not. I'll look that up in a moment), or, more likely, there are extra characters (spaces, or otherwise nor printable characters) after the final extension. e.g. "PL.234234.gnucash " (note the space there) or some such.
to see if you can list those files. If you can, then you have the answer (extra characters).
Otherwise, which shell are you trying this in? Is it in a shell, or some other application?