I would like the ability to query an index, specifically FTS indexes but also normal ones.

Whilst covered indexes resolve some use cases - I'd like the ability to run a regular expression query over an index, and also get a set of unique values back. For example - to query for all words in the FTS index matching a regex (and skipping over the index values with the same entry) so a REGEX for /.one./ on the index to get Jones,Bones,Phones and then that can become a FTS query to enable fuzzy search.