I played a lot of HOGs, but not all. Given the output of this genre since 2012, I think that is actually impossible for a single human, even as a job+hobby. I also find it difficult to really pinpoint single games. Especially since I actually loved the heck out of Vault Cracker: The Last Safe, which is at like 30% on Steam.
Plus I forgot many things since then or confuse games. These City Interactive ones just stirred some memories. Memories I had hoped to have forgotten by now.

Right now, as a series beyond Artifex Mundi, I'd say Danse Macabre managed to surprise me. A lot.
Supposedly, Cadenza is even better.
My all-time favourite HOG is Brink of Consciousness 1. It is also among the best games I played in general, regardless of genre.
A close second is probably Mystery of Unicorn Castle 2: The Beastmaster.
I personally found it too rich in backtracking, but a lot of HOG players absolutely love True Fear (the second episode is coming soon).
Maybe the Agency of Anomalies series, but it is old-school and the last episode seems to need WinXP to function (I played it on a VM).

Generally, I'd say try any random game from Elephant Games and possibly the Dark Parables series from Eipix. (They took over some other long-running series like the Mystery Case Files and the Hidden Expedition, but those games fluctuate in my opinion, just like their output in general outside those series.)
You can also try the Lost Lands or even better, the New York Mysteries series from FIVE-BN Games. The rest of their portfolio is kinda hit and miss. Mostly miss. Large miss.
Or, if you want a good laugh, hunt down Mysteryville 1-2. They are mega old-school and so incredibly bad and dumb that they are funny by today's standards.

Thanks. That's all I needed to know :/ Shame, because so cheap.... oh well.

Yeah its a good deal, I got all of them from there, but I guess it's good to have DRM-Free copies too.

i cant use it on any bundles, not even 10$/eur one