Okay, this is too cool not to post.
If you're trying to determine if you'd like to try Christie's non-Marple/Poirot short stories or the standalone novels, there's a widget on the
bibliography of her official website which does something really nifty.
If you click the Filter button, some dropdowns pop up and you can select by, among other things, Location and Murder Method*.
So if you have this secret fetish for reading whodunnits involving in-house stranglings, well, you're in luck, because there are 13 of them† to choose from.
It turns out there's a Mr. Quin story set in Canada. I have to get that collection, now.
(ETA: It turns out they've also a handy reading downloadable list for Christie in general, plus Poirot and Marple in specific, with suggested reading order to avoid spoilers for earlier books in later ones, and which you can use to check against the HC sale.)
* Mr. Green, in the hall, with the revolver.
† This method of story-selection may contain inadvertent spoilers. Viewer discretion is advised.