Request for Recs: Favourite (Short) Adventures for Favourite Games

I have recently been thinking about published adventures...

Personally, I tend to move back and forth between Call of Cthulhu and OSR-style games and while I really enjoy those systems, I find myself struggling with a lot of the adventures that are put out in support of them (not necessarily relevant but here is some context in the form of a blog post I wrote about my troubles).

One thing that has become obvious to me since returning to the hobby a few years back is that different games often wind up developing different cultures of play and part of that process of cultural development is the development of different approaches to adventure design.

Now... seeing as I am struggling with the approaches to adventure design favoured by the games I do play, I got a bit curious about the approaches to adventure design favoured by the games that I don't play, which brings me to my request:

Could you please recommend your favourite example of a short adventure for your favoured system. It doesn't matter what the system is but I would like the recs to be short adventures rather than extended campaigns even if the extended campaigns are what your favoured system is best known for (So no Kingmaker, Masks of Nyarlathotep, or Enemy Within please).

I'm just curious to see what's out there...