pgrouting

Elizabeth Chistensen already gave a succinct summary of some of the PostGIS Day 2022 presentations, which you can see here.

There were many case study presentations which involved use of PostGIS, QGIS, OpenStreetMap, and pgRouting (and other extensions that extend PostGIS) as well as many "How to" videos. There were also talks on "How PostGIS is made". I'll highlight some of these, which overlap with Elizabeth's list but different angle of view.