One thing I often need is Replaceing proper opening and closing double quotes (like “…”) with the plain straight double quotes ("…"). - A pain to do with a search replace tool!
Therefore it would be great to replace in the given selection all curly quotes with straight ones. But of course this could be generalised to single quotes and for both directions.
Please note that this is different to the current ‘Quotes’ extension, which puts quotes around the selection.