List of Sheet Names

The standard way of doing this is to create a Named Range (called, e.g. S_List)

=MID(TRANSPOSE(GET.WORKBOOK(1))&T(NOW()),FIND("]",TRANSPOSE(GET.WORKBOOK(1))&T(NOW()))+1,255)

Set up from the Name Manager (CTRL-F3)

then

=S_List

The file MUST be saved as .xlsm to allow GET.WORKBOOK to function.