Frankly, only Hidden Folks.
I've played and enjoyed many h.o.g. and found the concept delightful when it was new (the mystery case files series), but i grew to loathe it as a genre. As a very very very derivative and endlessly mindlessly cloned genre. I grew allergic to their plots, characters, hidden object and minigames justification, vaguely mystical or mythological atmosphere, and now i see them as the horrible cheap purple litterature shelves in the bookshop. There is none of them that i personally wish to acquire.
So, maybe gog should have the Mystery Files for historical purposes, maybe the Travelogue 360 too for the panoramic gimmick (have they thought of putting it in VR?). But beyond that, there is zero title that I'd point to for a wishlist.
But Hidden Folks makes something fresh and fun with the concept, so, I voted for it (and showed it in the Screenshot Thread a while ago). And also :
Hero of the Kingdom 1&2. It's very very casual, but, like Hidden Folks, it takes the "find # items on the screen" concept to make something a bit different with it. So, I prefer that sort of game rather than the 649873th version of "find your husband stolen by the witch ghost in the cursed theme park because of the malediction of the pharaos/lochness/bermudatriangle/quetzacoatl/lastthingwereadaboutinthatsummermagazine". Seriously, the whole genre now feels 100% written by Stephenie Meyer.
Edit : Regardless of plots and settings, I'd also be interested in H.O.G. that offer a particularly wide variety of selectabl languages, because they are excellent training tools. But I don't have specific exemples in mind.