Samsungs mostly, also shift and a few older models. Although, some have a crutch called displaylink, which basically encapsulates video signal over USB in software, while dp alt mode kinda* connects those same wires to the displayport output of the SoC (which is better due to having little to no overhead as well as ~no need for specialized overcomplicated hardware).
Also, some of the older models, like my beloved oneplus 6, don't even support USB 3, so dp alt mode is physically impossible for those.
* iirc, on qualcomms at least the SoC itself multiplexes USB 3 with dp (as in, it can be configured to output usb3 or dp on the same data lines), but I'm not sure how the switching itself is triggered, so there may or may not be a need to add another IC that'll handle communications over CC lines and tell the SoC when to use which. I personally suppose the SoCs should be able to handle everything themselves, tho.
Not the brightest of those, imo: a while back they've opted their users in "discover together", which is basically sharing your watch history with your plex friends. That went over as well as you'd expect: https://www.404media.co/plex-users-fear-discover-together-week-in-review-feature-will-leak-porn-habits-to-their-friends-and-family/