The names of hidden files start with `.` (dot), there are none that start with `b`.  To list names starting with `.b` use

    $ ls .b*

This will also list the contents of any directory whose name starts with `.b`.

To avoid listing the contents of directories, use

    $ ls -d .b*

To only list the names of _regular files_ whose names start with `.b`, use

    $ for name in .b*; do test -f "$name" && printf '%s\n' "$name"; done

To get the output in a similar way as with plain `ls`:

    $ for name in .b*; do test -f "$name" && printf '%s\n' "$name"; done | column