I know about the ["standard" special katakana](http://www.guidetojapanese.org/learn/grammar/katakana), like ファ *fa*, ディ *di*, ヴ *vu*, etc.  However, I keep running into others I can't find on any list, including the ones in *[What special kana are used to write foreign words?](http://japanese.stackexchange.com/questions/15119/what-special-kana-are-used-to-write-foreign-words)*

For example, on [this Wikipedia page](https://en.wikipedia.org/wiki/Zero_Escape:_Virtue%27s_Last_Reward#Main_characters), one character has the name:

> **Quark** (クォーク Kwōku)

I've never seen クォ *kwo* in any katakana list.

Another example is フュ *fyu*, as in the new movie [X-MEN: フューチャー&パスト](https://ja.wikipedia.org/wiki/X-MEN:_%E3%83%95%E3%83%A5%E3%83%BC%E3%83%81%E3%83%A3%E3%83%BC%26%E3%83%91%E3%82%B9%E3%83%88).

So, **what are all the "non-standard" katakana in regular use?**