Views String Select

This module provides views exposed filter for selecting a string from the list with selectable widget type (selector or radio buttons).

If you set "Variants of the string value" option to
"A|B|C|D|E|F|G|H|I|J|K|L|M|N|O|P|Q|R|S|T|U|V|W|X|Y|Z"
and set "Method of variant list limiting" option to "Hide variant",
the filter widget will appear which shows only letters which are relevant (this means selecting a letter in the filter will produce nonempty result).
The relevance can mean two different possibilities:
- unfiltered result of the view is considered
- result with the currently applied exposed filters is considered