reftex-ref-style-default-list

reftex-ref-style-default-list is a variable defined in `reftex-vars.el'.
Its value is

("Default")

Documentation:
List of reference styles to be activated by default.
The order is significant and controls the order in which macros
can be cycled in the buffer for selecting a label. The entries
in the list have to match the respective reference style names
used in the variable `reftex-ref-style-alist'.

You can customize this variable.

This variable was introduced, or its default value was changed, in version 24.3 of Emacs.