I know about the "special" Katakana that are typically taught, like ファ fa, ディ di, etc. However, I keep running into others that aren't found on any Katakana lists I've ever seen, including the one in this question.

For example, on this wikipedia page, one of the character's name is listed as:

Quark (クォーク Kuōku?)

I asked my friend who is fluent in Japanese why "kuo" is written クォ and not クオ, and he said "The correct romanization for クォ is kwo." I've never seen クォ in any Katakana list.

Another example I haven't seen anywhere is フュ fyu, seen in the new movie X-MEN: フューチャー&パスト.

So, is there a complete list of Katakana somewhere online?